por: add hex print of PoR values

this is for debugging, not to be merged in its current form

Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>

dagger/por/backends/backend_blst.nim

@@ -13,6 +13,7 @@
 
 import blscurve
 import blscurve/blst/blst_abi
+import stew/byteutils # for toHex
 
 type
   ec_SecretKey* = blscurve.SecretKey
@@ -108,4 +109,27 @@ func ec_verify*[T: byte|char](
        publicKey: PublicKey,
        message: openarray[T],
        signature: Signature) : bool =
-  verify(publicKey, message, signature)
+  verify(publicKey, message, signature)
+
+func toHex*(
+       obj: blst_p1|blst_p2|ec_scalar,
+     ): string =
+  ## Return the hex representation of a BLS object
+  ## They are serialized in compressed form
+  when obj is blst_p1:
+    const size = 48
+    var bytes{.noInit.}: array[size, byte]
+    bytes.blst_p1_compress(obj)
+  elif obj is blst_p2:
+    const size = 96
+    var bytes{.noInit.}: array[size, byte]
+    bytes.blst_p2_compress(obj)
+  elif obj is blst_scalar:
+    const size = 32
+    var bytes{.noInit.}: array[size, byte]
+    bytes.blst_bendian_from_scalar(obj)
+
+  result = bytes.toHex()
+
+proc `$`*(x: ec_p1|ec_p2|ec_scalar): string =
+  result &= toHex(x)

dagger/por/backends/backend_constantine.nim

@@ -22,6 +22,7 @@ import
   # constantine/math/pairing/cyclotomic_subgroup,
   # constantine/math/io/io_extfields,
   constantine/math/io/io_bigints,
+  constantine/math/io/io_ec,
   # constantine/math/config/[curves_declaration, type_ff],
   constantine/math/config/type_ff,
   constantine/blssig_pop_on_bls12381_g2,
@@ -187,3 +188,6 @@ func ec_verify*(
        message: openarray[char],
        signature: Signature) : bool =
   publicKey.verify(message, signature) == cttBLS_Success
+
+proc `$`*(x: ec_p1|ec_p2|ec_scalar): string =
+  result &= toHex(x)

dagger/por/por.nim

@@ -83,10 +83,13 @@
 #  - constantine is more experimental, supports BLS and BN curves as well
 # As of now configuration of backends is in the backend_* file itself
 import ./backends/backend_blst
+export backend_blst.`$`
 #import ./backends/backend_constantine
+#export backend_constantine.`$`
 
 import ../rng
 import endians
+import pkg/stew/byteutils
 
 # sector size in bytes. Must be smaller than the subgroup order r
 # which is 255 bits long for BLS12-381
@@ -361,3 +364,11 @@ proc verifyProof*(tau: Tau, q: openArray[QElement], mus: openArray[ec_scalar], s
   g.ec_p2_from_affine(EC_G2)
 
   return verifyPairings(sum, spk.key, sigma, g)
+
+proc `$`*(t0: TauZero): string =
+  result &= "\nname: " & toHex(t0.name)
+  result &= "\nn: " & $t0.n
+  result &= "\nu: " & $t0.u
+
+proc `$`*(x: array[96, byte]): string =
+  result &= toHex(x)

dagger/por/testpor.nim

@@ -20,15 +20,16 @@ proc testbls() : bool =
 
   benchmark "Auth generation (s=" & $sectorsperblock & ")":
     let (tau, authenticators) = por.setup(ssk, sectorsperblock, "example.txt")
-  #echo "Auth: ", authenticators
+  echo "tau: ", tau
+  echo "Auth: ", authenticators
 
   benchmark "Generating challenge (q=" & $querylen & ")":
     let q = por.generateQuery(tau, spk, querylen)
-  #echo "Generated!" #, " q:", q
+  echo "Generated!", "\nq:", q
 
   benchmark "Issuing proof":
     let (mu, sigma) = por.generateProof(q, authenticators, spk, sectorsperblock, "example.txt")
-  #echo "Issued!" #, " mu:", mu, " sigma:", sigma
+  echo "Issued!", "\nmu:", mu, "\nsigma:", sigma
 
   benchmark "Verifying proof":
     result = por.verifyProof(tau, q, mu, sigma, spk)