diff --git a/build-aux/m4/ax_prog_cc_for_build.m4 b/build-aux/m4/ax_prog_cc_for_build.m4
index 77fd346..7bcbf32 100644
--- a/build-aux/m4/ax_prog_cc_for_build.m4
+++ b/build-aux/m4/ax_prog_cc_for_build.m4
@@ -1,5 +1,5 @@
 # ===========================================================================
-#   http://www.gnu.org/software/autoconf-archive/ax_prog_cc_for_build.html
+#   https://www.gnu.org/software/autoconf-archive/ax_prog_cc_for_build.html
 # ===========================================================================
 #
 # SYNOPSIS
diff --git a/contrib/lax_der_parsing.c b/contrib/lax_der_parsing.c
index f71db4b..c1627e3 100644
--- a/contrib/lax_der_parsing.c
+++ b/contrib/lax_der_parsing.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include <string.h>
 #include <secp256k1.h>
diff --git a/contrib/lax_der_parsing.h b/contrib/lax_der_parsing.h
index 7eaf63b..6b7255e 100644
--- a/contrib/lax_der_parsing.h
+++ b/contrib/lax_der_parsing.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 /****
  * Please do not link this file directly. It is not part of the libsecp256k1
diff --git a/contrib/lax_der_privatekey_parsing.c b/contrib/lax_der_privatekey_parsing.c
index c2e63b4..429760f 100644
--- a/contrib/lax_der_privatekey_parsing.c
+++ b/contrib/lax_der_privatekey_parsing.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014, 2015 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014, 2015 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include <string.h>
 #include <secp256k1.h>
diff --git a/contrib/lax_der_privatekey_parsing.h b/contrib/lax_der_privatekey_parsing.h
index fece261..602c7c5 100644
--- a/contrib/lax_der_privatekey_parsing.h
+++ b/contrib/lax_der_privatekey_parsing.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014, 2015 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014, 2015 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 /****
  * Please do not link this file directly. It is not part of the libsecp256k1
diff --git a/contrib/travis.sh b/contrib/travis.sh
index 24cc931..ed98623 100755
--- a/contrib/travis.sh
+++ b/contrib/travis.sh
@@ -28,7 +28,7 @@ fi
 if [ "$RUN_VALGRIND" = "yes" ]
 then
     make -j2
-    # the `--error-exitcode` is required to make the test fail if valgrind found errors, otherwise it'll return 0 (http://valgrind.org/docs/manual/manual-core.html)
+    # the `--error-exitcode` is required to make the test fail if valgrind found errors, otherwise it'll return 0 (https://www.valgrind.org/docs/manual/manual-core.html)
     valgrind --error-exitcode=42 ./tests 16
     valgrind --error-exitcode=42 ./exhaustive_tests
 fi
diff --git a/sage/group_prover.sage b/sage/group_prover.sage
index 53ffee2..b200bfe 100644
--- a/sage/group_prover.sage
+++ b/sage/group_prover.sage
@@ -42,7 +42,7 @@
 #     as we assume that all constraints in it are complementary with each other.
 #
 # Based on the sage verification scripts used in the Explicit-Formulas Database
-# by Tanja Lange and others, see http://hyperelliptic.org/EFD
+# by Tanja Lange and others, see https://hyperelliptic.org/EFD
 
 class fastfrac:
   """Fractions over rings."""
diff --git a/src/asm/field_10x26_arm.s b/src/asm/field_10x26_arm.s
index 9a5bd06..5f68cef 100644
--- a/src/asm/field_10x26_arm.s
+++ b/src/asm/field_10x26_arm.s
@@ -1,9 +1,9 @@
 @ vim: set tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab syntax=armasm:
-/**********************************************************************
- * Copyright (c) 2014 Wladimir J. van der Laan                        *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Wladimir J. van der Laan                         *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 /*
 ARM implementation of field_10x26 inner loops.
 
diff --git a/src/assumptions.h b/src/assumptions.h
index 77204de..6dc527b 100644
--- a/src/assumptions.h
+++ b/src/assumptions.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2020 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2020 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ASSUMPTIONS_H
 #define SECP256K1_ASSUMPTIONS_H
diff --git a/src/basic-config.h b/src/basic-config.h
index b0d82e8..bb6b582 100644
--- a/src/basic-config.h
+++ b/src/basic-config.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_BASIC_CONFIG_H
 #define SECP256K1_BASIC_CONFIG_H
diff --git a/src/bench.h b/src/bench.h
index 9bfed90..63c55df 100644
--- a/src/bench.h
+++ b/src/bench.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_BENCH_H
 #define SECP256K1_BENCH_H
diff --git a/src/bench_ecdh.c b/src/bench_ecdh.c
index f099d33..ab4b8f4 100644
--- a/src/bench_ecdh.c
+++ b/src/bench_ecdh.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra                  *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra                   *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include <string.h>
 
diff --git a/src/bench_ecmult.c b/src/bench_ecmult.c
index facd07e..85b9e43 100644
--- a/src/bench_ecmult.c
+++ b/src/bench_ecmult.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2017 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2017 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 #include <stdio.h>
 
 #include "include/secp256k1.h"
diff --git a/src/bench_internal.c b/src/bench_internal.c
index 5f2b7a9..7fa6882 100644
--- a/src/bench_internal.c
+++ b/src/bench_internal.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014-2015 Pieter Wuille                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 #include <stdio.h>
 
 #include "include/secp256k1.h"
diff --git a/src/bench_recover.c b/src/bench_recover.c
index e952ed1..3f6270c 100644
--- a/src/bench_recover.c
+++ b/src/bench_recover.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014-2015 Pieter Wuille                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include "include/secp256k1.h"
 #include "include/secp256k1_recovery.h"
diff --git a/src/bench_schnorrsig.c b/src/bench_schnorrsig.c
index 315f5af..f7f591c 100644
--- a/src/bench_schnorrsig.c
+++ b/src/bench_schnorrsig.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick                *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick                 *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include <string.h>
 #include <stdlib.h>
diff --git a/src/bench_sign.c b/src/bench_sign.c
index 0fd6c00..933f367 100644
--- a/src/bench_sign.c
+++ b/src/bench_sign.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include "include/secp256k1.h"
 #include "util.h"
diff --git a/src/bench_verify.c b/src/bench_verify.c
index c9efa5f..c56aefd 100644
--- a/src/bench_verify.c
+++ b/src/bench_verify.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include <stdio.h>
 #include <string.h>
diff --git a/src/ecdsa.h b/src/ecdsa.h
index 80590c7..d5e54d8 100644
--- a/src/ecdsa.h
+++ b/src/ecdsa.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECDSA_H
 #define SECP256K1_ECDSA_H
diff --git a/src/ecdsa_impl.h b/src/ecdsa_impl.h
index 5f54b59..156a33d 100644
--- a/src/ecdsa_impl.h
+++ b/src/ecdsa_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013-2015 Pieter Wuille                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 
 #ifndef SECP256K1_ECDSA_IMPL_H
diff --git a/src/eckey.h b/src/eckey.h
index b621f1e..5be3a64 100644
--- a/src/eckey.h
+++ b/src/eckey.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECKEY_H
 #define SECP256K1_ECKEY_H
diff --git a/src/eckey_impl.h b/src/eckey_impl.h
index e2e72d9..a39cb79 100644
--- a/src/eckey_impl.h
+++ b/src/eckey_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECKEY_IMPL_H
 #define SECP256K1_ECKEY_IMPL_H
diff --git a/src/ecmult.h b/src/ecmult.h
index 09e8146..7aa394a 100644
--- a/src/ecmult.h
+++ b/src/ecmult.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra      *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra       *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECMULT_H
 #define SECP256K1_ECMULT_H
diff --git a/src/ecmult_const.h b/src/ecmult_const.h
index 03bb332..d6f0ea2 100644
--- a/src/ecmult_const.h
+++ b/src/ecmult_const.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECMULT_CONST_H
 #define SECP256K1_ECMULT_CONST_H
diff --git a/src/ecmult_const_impl.h b/src/ecmult_const_impl.h
index bb95111..0e1fb96 100644
--- a/src/ecmult_const_impl.h
+++ b/src/ecmult_const_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra                  *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra                   *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECMULT_CONST_IMPL_H
 #define SECP256K1_ECMULT_CONST_IMPL_H
diff --git a/src/ecmult_gen.h b/src/ecmult_gen.h
index 30815e5..539618d 100644
--- a/src/ecmult_gen.h
+++ b/src/ecmult_gen.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECMULT_GEN_H
 #define SECP256K1_ECMULT_GEN_H
diff --git a/src/ecmult_gen_impl.h b/src/ecmult_gen_impl.h
index 30ac165..384a67f 100644
--- a/src/ecmult_gen_impl.h
+++ b/src/ecmult_gen_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell      *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell       *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_ECMULT_GEN_IMPL_H
 #define SECP256K1_ECMULT_GEN_IMPL_H
@@ -144,7 +144,7 @@ static void secp256k1_ecmult_gen(const secp256k1_ecmult_gen_context *ctx, secp25
              *    (https://cryptojedi.org/peter/data/chesrump-20130822.pdf) and
              *   "Cache Attacks and Countermeasures: the Case of AES", RSA 2006,
              *    by Dag Arne Osvik, Adi Shamir, and Eran Tromer
-             *    (http://www.tau.ac.il/~tromer/papers/cache.pdf)
+             *    (https://www.tau.ac.il/~tromer/papers/cache.pdf)
              */
             secp256k1_ge_storage_cmov(&adds, &(*ctx->prec)[j][i], i == bits);
         }
diff --git a/src/ecmult_impl.h b/src/ecmult_impl.h
index caa87e3..5c2edac 100644
--- a/src/ecmult_impl.h
+++ b/src/ecmult_impl.h
@@ -1,8 +1,8 @@
-/*****************************************************************************
- * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra, Jonas Nick *
- * Distributed under the MIT software license, see the accompanying          *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.       *
- *****************************************************************************/
+/******************************************************************************
+ * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra, Jonas Nick  *
+ * Distributed under the MIT software license, see the accompanying           *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.       *
+ ******************************************************************************/
 
 #ifndef SECP256K1_ECMULT_IMPL_H
 #define SECP256K1_ECMULT_IMPL_H
diff --git a/src/field.h b/src/field.h
index aca1fb7..0e5c385 100644
--- a/src/field.h
+++ b/src/field.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_FIELD_H
 #define SECP256K1_FIELD_H
diff --git a/src/field_10x26.h b/src/field_10x26.h
index 5ff03c8..9eb6560 100644
--- a/src/field_10x26.h
+++ b/src/field_10x26.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_FIELD_REPR_H
 #define SECP256K1_FIELD_REPR_H
diff --git a/src/field_10x26_impl.h b/src/field_10x26_impl.h
index 651500e..62bffdc 100644
--- a/src/field_10x26_impl.h
+++ b/src/field_10x26_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_FIELD_REPR_IMPL_H
 #define SECP256K1_FIELD_REPR_IMPL_H
diff --git a/src/field_5x52.h b/src/field_5x52.h
index 6a06848..50ee3f9 100644
--- a/src/field_5x52.h
+++ b/src/field_5x52.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_FIELD_REPR_H
 #define SECP256K1_FIELD_REPR_H
diff --git a/src/field_5x52_asm_impl.h b/src/field_5x52_asm_impl.h
index 1fc3171..a211804 100644
--- a/src/field_5x52_asm_impl.h
+++ b/src/field_5x52_asm_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013-2014 Diederik Huys, Pieter Wuille               *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013-2014 Diederik Huys, Pieter Wuille                *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 /**
  * Changelog:
diff --git a/src/field_5x52_impl.h b/src/field_5x52_impl.h
index 71a38f9..3465ea3 100644
--- a/src/field_5x52_impl.h
+++ b/src/field_5x52_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_FIELD_REPR_IMPL_H
 #define SECP256K1_FIELD_REPR_IMPL_H
diff --git a/src/field_5x52_int128_impl.h b/src/field_5x52_int128_impl.h
index bcbfb92..314002e 100644
--- a/src/field_5x52_int128_impl.h
+++ b/src/field_5x52_int128_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_FIELD_INNER5X52_IMPL_H
 #define SECP256K1_FIELD_INNER5X52_IMPL_H
diff --git a/src/field_impl.h b/src/field_impl.h
index 18e4d2f..7ebb6d7 100644
--- a/src/field_impl.h
+++ b/src/field_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_FIELD_IMPL_H
 #define SECP256K1_FIELD_IMPL_H
diff --git a/src/gen_context.c b/src/gen_context.c
index 8b7729a..b08ac3b 100644
--- a/src/gen_context.c
+++ b/src/gen_context.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014, 2015 Thomas Daede, Cory Fields           *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014, 2015 Thomas Daede, Cory Fields            *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 // Autotools creates libsecp256k1-config.h, of which ECMULT_GEN_PREC_BITS is needed.
 // ifndef guard so downstream users can define their own if they do not use autotools.
diff --git a/src/group.h b/src/group.h
index 36e39ec..426c286 100644
--- a/src/group.h
+++ b/src/group.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_GROUP_H
 #define SECP256K1_GROUP_H
diff --git a/src/group_impl.h b/src/group_impl.h
index ce84542..79177d7 100644
--- a/src/group_impl.h
+++ b/src/group_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_GROUP_IMPL_H
 #define SECP256K1_GROUP_IMPL_H
diff --git a/src/hash.h b/src/hash.h
index de26e4b..0947a09 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_HASH_H
 #define SECP256K1_HASH_H
diff --git a/src/hash_impl.h b/src/hash_impl.h
index 4097725..f8cd3a1 100644
--- a/src/hash_impl.h
+++ b/src/hash_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_HASH_IMPL_H
 #define SECP256K1_HASH_IMPL_H
diff --git a/src/modules/ecdh/main_impl.h b/src/modules/ecdh/main_impl.h
index 07a25b8..1ac6708 100644
--- a/src/modules/ecdh/main_impl.h
+++ b/src/modules/ecdh/main_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_MODULE_ECDH_MAIN_H
 #define SECP256K1_MODULE_ECDH_MAIN_H
diff --git a/src/modules/ecdh/tests_impl.h b/src/modules/ecdh/tests_impl.h
index e8d2aea..be07447 100644
--- a/src/modules/ecdh/tests_impl.h
+++ b/src/modules/ecdh/tests_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_MODULE_ECDH_TESTS_H
 #define SECP256K1_MODULE_ECDH_TESTS_H
diff --git a/src/modules/extrakeys/main_impl.h b/src/modules/extrakeys/main_impl.h
index e365f92..e8beaa3 100644
--- a/src/modules/extrakeys/main_impl.h
+++ b/src/modules/extrakeys/main_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2020 Jonas Nick                                      *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2020 Jonas Nick                                       *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_MODULE_EXTRAKEYS_MAIN_
 #define _SECP256K1_MODULE_EXTRAKEYS_MAIN_
diff --git a/src/modules/extrakeys/tests_exhaustive_impl.h b/src/modules/extrakeys/tests_exhaustive_impl.h
index 0e29bc6..d78c315 100644
--- a/src/modules/extrakeys/tests_exhaustive_impl.h
+++ b/src/modules/extrakeys/tests_exhaustive_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2020 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2020 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_MODULE_EXTRAKEYS_TESTS_EXHAUSTIVE_
 #define _SECP256K1_MODULE_EXTRAKEYS_TESTS_EXHAUSTIVE_
diff --git a/src/modules/extrakeys/tests_impl.h b/src/modules/extrakeys/tests_impl.h
index 5ee1358..5b15968 100644
--- a/src/modules/extrakeys/tests_impl.h
+++ b/src/modules/extrakeys/tests_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2020 Jonas Nick                                      *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2020 Jonas Nick                                       *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_MODULE_EXTRAKEYS_TESTS_
 #define _SECP256K1_MODULE_EXTRAKEYS_TESTS_
diff --git a/src/modules/recovery/main_impl.h b/src/modules/recovery/main_impl.h
index d827b89..7a440a7 100644
--- a/src/modules/recovery/main_impl.h
+++ b/src/modules/recovery/main_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013-2015 Pieter Wuille                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_MODULE_RECOVERY_MAIN_H
 #define SECP256K1_MODULE_RECOVERY_MAIN_H
diff --git a/src/modules/recovery/tests_exhaustive_impl.h b/src/modules/recovery/tests_exhaustive_impl.h
index a2f381d..0ba9409 100644
--- a/src/modules/recovery/tests_exhaustive_impl.h
+++ b/src/modules/recovery/tests_exhaustive_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2016 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2016 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_MODULE_RECOVERY_EXHAUSTIVE_TESTS_H
 #define SECP256K1_MODULE_RECOVERY_EXHAUSTIVE_TESTS_H
diff --git a/src/modules/recovery/tests_impl.h b/src/modules/recovery/tests_impl.h
index 09cae38..40dba87 100644
--- a/src/modules/recovery/tests_impl.h
+++ b/src/modules/recovery/tests_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013-2015 Pieter Wuille                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_MODULE_RECOVERY_TESTS_H
 #define SECP256K1_MODULE_RECOVERY_TESTS_H
diff --git a/src/modules/schnorrsig/main_impl.h b/src/modules/schnorrsig/main_impl.h
index da747fe..902025c 100644
--- a/src/modules/schnorrsig/main_impl.h
+++ b/src/modules/schnorrsig/main_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick                *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick                 *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_MODULE_SCHNORRSIG_MAIN_
 #define _SECP256K1_MODULE_SCHNORRSIG_MAIN_
diff --git a/src/modules/schnorrsig/tests_exhaustive_impl.h b/src/modules/schnorrsig/tests_exhaustive_impl.h
index 4bf0bc1..7e6a1e7 100644
--- a/src/modules/schnorrsig/tests_exhaustive_impl.h
+++ b/src/modules/schnorrsig/tests_exhaustive_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2020 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2020 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_
 #define _SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_
diff --git a/src/modules/schnorrsig/tests_impl.h b/src/modules/schnorrsig/tests_impl.h
index f522fcb..e10c45f 100644
--- a/src/modules/schnorrsig/tests_impl.h
+++ b/src/modules/schnorrsig/tests_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick                *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick                 *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_MODULE_SCHNORRSIG_TESTS_
 #define _SECP256K1_MODULE_SCHNORRSIG_TESTS_
diff --git a/src/num.h b/src/num.h
index 49f2dd7..59a5cf2 100644
--- a/src/num.h
+++ b/src/num.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_NUM_H
 #define SECP256K1_NUM_H
diff --git a/src/num_gmp.h b/src/num_gmp.h
index 3619844..cc6c51a 100644
--- a/src/num_gmp.h
+++ b/src/num_gmp.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_NUM_REPR_H
 #define SECP256K1_NUM_REPR_H
diff --git a/src/num_gmp_impl.h b/src/num_gmp_impl.h
index 0ae2a8b..c07947d 100644
--- a/src/num_gmp_impl.h
+++ b/src/num_gmp_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_NUM_REPR_IMPL_H
 #define SECP256K1_NUM_REPR_IMPL_H
diff --git a/src/num_impl.h b/src/num_impl.h
index c45193b..880598e 100644
--- a/src/num_impl.h
+++ b/src/num_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_NUM_IMPL_H
 #define SECP256K1_NUM_IMPL_H
diff --git a/src/scalar.h b/src/scalar.h
index fb3fb18..0b737f9 100644
--- a/src/scalar.h
+++ b/src/scalar.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_H
 #define SECP256K1_SCALAR_H
diff --git a/src/scalar_4x64.h b/src/scalar_4x64.h
index 19c7495..7009642 100644
--- a/src/scalar_4x64.h
+++ b/src/scalar_4x64.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_REPR_H
 #define SECP256K1_SCALAR_REPR_H
diff --git a/src/scalar_4x64_impl.h b/src/scalar_4x64_impl.h
index 73cbd5e..3eaa041 100644
--- a/src/scalar_4x64_impl.h
+++ b/src/scalar_4x64_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_REPR_IMPL_H
 #define SECP256K1_SCALAR_REPR_IMPL_H
diff --git a/src/scalar_8x32.h b/src/scalar_8x32.h
index 2c9a348..17863ef 100644
--- a/src/scalar_8x32.h
+++ b/src/scalar_8x32.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_REPR_H
 #define SECP256K1_SCALAR_REPR_H
diff --git a/src/scalar_8x32_impl.h b/src/scalar_8x32_impl.h
index 6853f79..bf98e01 100644
--- a/src/scalar_8x32_impl.h
+++ b/src/scalar_8x32_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_REPR_IMPL_H
 #define SECP256K1_SCALAR_REPR_IMPL_H
diff --git a/src/scalar_impl.h b/src/scalar_impl.h
index fc75891..61c1fbd 100644
--- a/src/scalar_impl.h
+++ b/src/scalar_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2014 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_IMPL_H
 #define SECP256K1_SCALAR_IMPL_H
diff --git a/src/scalar_low.h b/src/scalar_low.h
index 2794a7f..67051bd 100644
--- a/src/scalar_low.h
+++ b/src/scalar_low.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_REPR_H
 #define SECP256K1_SCALAR_REPR_H
diff --git a/src/scalar_low_impl.h b/src/scalar_low_impl.h
index a615ec0..98ffd15 100644
--- a/src/scalar_low_impl.h
+++ b/src/scalar_low_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2015 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2015 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SCALAR_REPR_IMPL_H
 #define SECP256K1_SCALAR_REPR_IMPL_H
diff --git a/src/scratch.h b/src/scratch.h
index 77b35d1..bb3172a 100644
--- a/src/scratch.h
+++ b/src/scratch.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2017 Andrew Poelstra	                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2017 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_SCRATCH_
 #define _SECP256K1_SCRATCH_
diff --git a/src/scratch_impl.h b/src/scratch_impl.h
index f381e2e..a2b78f8 100644
--- a/src/scratch_impl.h
+++ b/src/scratch_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2017 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2017 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef _SECP256K1_SCRATCH_IMPL_H_
 #define _SECP256K1_SCRATCH_IMPL_H_
diff --git a/src/secp256k1.c b/src/secp256k1.c
index 447d2c8..4f56c27 100644
--- a/src/secp256k1.c
+++ b/src/secp256k1.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013-2015 Pieter Wuille                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include "include/secp256k1.h"
 #include "include/secp256k1_preallocated.h"
diff --git a/src/selftest.h b/src/selftest.h
index 0e37510..52f1b84 100644
--- a/src/selftest.h
+++ b/src/selftest.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2020 Pieter Wuille                                   *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2020 Pieter Wuille                                    *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_SELFTEST_H
 #define SECP256K1_SELFTEST_H
diff --git a/src/testrand.h b/src/testrand.h
index a76003d..667d186 100644
--- a/src/testrand.h
+++ b/src/testrand.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_TESTRAND_H
 #define SECP256K1_TESTRAND_H
diff --git a/src/testrand_impl.h b/src/testrand_impl.h
index 3392566..e643778 100644
--- a/src/testrand_impl.h
+++ b/src/testrand_impl.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013-2015 Pieter Wuille                              *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_TESTRAND_IMPL_H
 #define SECP256K1_TESTRAND_IMPL_H
diff --git a/src/tests.c b/src/tests.c
index 743acbd..4636304 100644
--- a/src/tests.c
+++ b/src/tests.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell      *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell       *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #if defined HAVE_CONFIG_H
 #include "libsecp256k1-config.h"
diff --git a/src/tests_exhaustive.c b/src/tests_exhaustive.c
index f4d5b8e..2bb5381 100644
--- a/src/tests_exhaustive.c
+++ b/src/tests_exhaustive.c
@@ -1,8 +1,8 @@
 /***********************************************************************
- * Copyright (c) 2016 Andrew Poelstra                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+ * Copyright (c) 2016 Andrew Poelstra                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #if defined HAVE_CONFIG_H
 #include "libsecp256k1-config.h"
diff --git a/src/util.h b/src/util.h
index 2a9eb5a..931f71c 100644
--- a/src/util.h
+++ b/src/util.h
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2013, 2014 Pieter Wuille                             *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2013, 2014 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #ifndef SECP256K1_UTIL_H
 #define SECP256K1_UTIL_H
diff --git a/src/valgrind_ctime_test.c b/src/valgrind_ctime_test.c
index 3169e36..192b753 100644
--- a/src/valgrind_ctime_test.c
+++ b/src/valgrind_ctime_test.c
@@ -1,8 +1,8 @@
-/**********************************************************************
- * Copyright (c) 2020 Gregory Maxwell                                 *
- * Distributed under the MIT software license, see the accompanying   *
- * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
- **********************************************************************/
+/***********************************************************************
+ * Copyright (c) 2020 Gregory Maxwell                                  *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
 
 #include <valgrind/memcheck.h>
 #include "include/secp256k1.h"