diff --git a/bearssl/abi/bearssl_ec.nim b/bearssl/abi/bearssl_ec.nim
index add5aed..11336e4 100644
--- a/bearssl/abi/bearssl_ec.nim
+++ b/bearssl/abi/bearssl_ec.nim
@@ -325,10 +325,14 @@ const
   EC_KBUF_PUB_MAX_SIZE* = 145
 
 
-proc ecKeygen*(rngCtx: ptr ptr PrngClass; impl: ptr EcImpl; sk: ptr EcPrivateKey;
+proc ecKeygen*(rngCtx: PrngClassPointerConst; impl: ptr EcImpl; sk: ptr EcPrivateKey;
               kbuf: pointer; curve: cint): uint {.importcFunc, importc: "br_ec_keygen",
     header: "bearssl_ec.h".}
 
+proc ecKeygen*(rngCtx: ptr ptr PrngClass; impl: ptr EcImpl; sk: ptr EcPrivateKey;
+              kbuf: pointer; curve: cint): uint =
+  ecKeygen(PrngClassPointerConst(rngCtx), impl, sk, kbuf, curve)
+
 proc ecComputePub*(impl: ptr EcImpl; pk: ptr EcPublicKey; kbuf: pointer;
                   sk: ptr EcPrivateKey): uint {.importcFunc,
     importc: "br_ec_compute_pub", header: "bearssl_ec.h".}
diff --git a/bearssl/abi/bearssl_rand.nim b/bearssl/abi/bearssl_rand.nim
index d296d1a..63c8c7e 100644
--- a/bearssl/abi/bearssl_rand.nim
+++ b/bearssl/abi/bearssl_rand.nim
@@ -21,6 +21,7 @@ type
     update* {.importc: "update".}: proc (ctx: ptr ptr PrngClass; seed: pointer;
                                      seedLen: uint) {.importcFunc.}
 
+  PrngClassPointerConst* {.importc: "const br_prng_class**", header: "bearssl_rand.h", bycopy.} = pointer
 
 
 type
@@ -51,7 +52,7 @@ proc hmacDrbgGetHash*(ctx: var HmacDrbgContext): ptr HashClass {.inline.} =
 
 
 type
-  PrngSeeder* {.importc: "br_prng_seeder".} = proc (ctx: ptr ptr PrngClass): cint {.importcFunc.}
+  PrngSeeder* {.importc: "br_prng_seeder".} = proc (ctx: PrngClassPointerConst): cint {.importcFunc.}
   constCstringArray* {.importc: "const char**", nodecl.} = pointer
 
 proc prngSeederSystem*(name: constCstringArray): PrngSeeder {.importcFunc,
diff --git a/bearssl/abi/brssl.nim b/bearssl/abi/brssl.nim
index c3231a0..ee94e05 100644
--- a/bearssl/abi/brssl.nim
+++ b/bearssl/abi/brssl.nim
@@ -18,8 +18,11 @@ type
     vtable* {.importc: "vtable".}: ptr X509Class
     inner* {.importc: "inner".}: ptr ptr X509Class
 
-proc x509NoanchorInit*(xwc: var X509NoanchorContext; inner: ptr ptr X509Class) {.importcFunc,
+proc x509NoanchorInit*(xwc: var X509NoanchorContext; inner: X509ClassPointerConst) {.importcFunc,
     importc: "x509_noanchor_init", header: "brssl_cpp.h".}
 
+proc x509NoanchorInit*(xwc: var X509NoanchorContext; inner: ptr ptr X509Class) =
+  x509NoanchorInit(xwc, X509ClassPointerConst(inner))
+
 proc initNoAnchor*(xwc: var X509NoanchorContext, inner: ptr ptr X509Class) {.
      importcFunc, importc: "x509_noanchor_init", header: "brssl_cpp.h", deprecated: "x509NoanchorInit".}
diff --git a/bearssl/rand.nim b/bearssl/rand.nim
index a12ee94..81f383b 100644
--- a/bearssl/rand.nim
+++ b/bearssl/rand.nim
@@ -39,7 +39,7 @@ proc new*(T: type HmacDrbgContext): ref HmacDrbgContext =
   let rng = (ref HmacDrbgContext)()
   hmacDrbgInit(rng[], addr sha256Vtable, nil, 0)
 
-  if seeder(addr rng.vtable) == 0:
+  if seeder(PrngClassPointerConst(addr rng.vtable)) == 0:
     return nil
 
   rng