Addded non-recoverable signature type and routines

eth/keys/libsecp256k1.nim

@@ -13,7 +13,8 @@ import secp256k1, nimcrypto/sysrand, nimcrypto/utils
 const
   KeyLength* = 256 div 8
   CompressedPubKeyLength* = 33
-  RawSignatureSize* = KeyLength * 2 + 1
+  RawSignatureNRSize* = KeyLength * 2 # Non-recoverable signature
+  RawSignatureSize* = RawSignatureNRSize + 1 # Recoverable
   RawPublicKeySize* = KeyLength * 2
   InvalidPrivateKey = "Invalid private key!"
   InvalidPublicKey = "Invalid public key!"
@@ -33,6 +34,11 @@ type
     ## Representation of ECDH shared secret
     data*: array[KeyLength, byte]
 
+  SharedSecretFull* = object
+    ## Representation of ECDH shared secret, with leading `y` byte
+    # (`y` is 0x02 when pubkey.y is even or 0x03 when odd)
+    data*: array[1 + KeyLength, byte]
+
   KeyPair* = object
     ## Representation of private/public keys pair
     seckey*: PrivateKey
@@ -41,6 +47,9 @@ type
   Signature* = secp256k1_ecdsa_recoverable_signature
     ## Representation of signature
 
+  SignatureNR* = secp256k1_ecdsa_signature
+    ## Representation of non-recoverable signature
+
   Secp256k1Exception* = object of Exception
     ## Exceptions generated by `libsecp256k1`
 
@@ -175,12 +184,23 @@ proc recoverPublicKey*(data: openarray[byte],
 
   result = EthKeysStatus.Success
 
-proc recoverSignature*(data: openarray[byte],
-                       signature: var Signature): EthKeysStatus =
+proc parseCompact*(signature: var SignatureNR, data: openarray[byte]): EthKeysStatus =
+  let ctx = getSecpContext()
+  let length = len(data)
+  if length == RawSignatureNRSize:
+    if secp256k1_ecdsa_signature_parse_compact(ctx, addr signature,
+                                    cast[ptr cuchar](unsafeAddr data[0])) != 1:
+      return(EthKeysStatus.Error)
+  else:
+    setErrorMsg(InvalidSignature)
+    return(EthKeysStatus.Error)
+  result = EthKeysStatus.Success
+
+proc parseCompact*(signature: var Signature, data: openarray[byte]): EthKeysStatus =
   ## Unserialize signature from `data`.
   let ctx = getSecpContext()
   let length = len(data)
-  if length < RawSignatureSize:
+  if length != RawSignatureSize:
     setErrorMsg(InvalidSignature)
     return(EthKeysStatus.Error)
   var recid = cint(data[KeyLength * 2])
@@ -190,6 +210,14 @@ proc recoverSignature*(data: openarray[byte],
     return(EthKeysStatus.Error)
   result = EthKeysStatus.Success
 
+proc recoverSignature*(data: openarray[byte],
+                       signature: var Signature): EthKeysStatus {.deprecated.} =
+  ## Deprecated, use `parseCompact` instead
+  if data.len < RawSignatureSize:
+    setErrorMsg(InvalidSignature)
+    return(EthKeysStatus.Error)
+  signature.parseCompact(data.toOpenArray(0, RawSignatureSize - 1))
+
 proc initPublicKey*(hexstr: string): PublicKey =
   ## Create new public key from hexadecimal string representation.
   var o = fromHex(stripSpaces(hexstr))
@@ -212,6 +240,16 @@ proc initSignature*(data: openarray[byte]): Signature =
   if recoverSignature(data, result) != EthKeysStatus.Success:
     raise newException(EthKeysException, libsecp256k1ErrorMsg())
 
+proc ecdhAgree*(seckey: PrivateKey, pubkey: PublicKey,
+                    secret: var SharedSecretFull): EthKeysStatus =
+  ## Calculate ECDH shared secret.
+  let ctx = getSecpContext()
+  if secp256k1_ecdh_raw(ctx, cast[ptr cuchar](addr secret.data),
+                        unsafeAddr pubkey,
+                        cast[ptr cuchar](unsafeAddr seckey)) != 1:
+    return(EthKeysStatus.Error)
+  return(EthKeysStatus.Success)
+
 proc ecdhAgree*(seckey: PrivateKey, pubkey: PublicKey,
                 secret: var SharedSecret): EthKeysStatus =
   ## Calculate ECDH shared secret.
@@ -255,15 +293,6 @@ proc getRawCompressed*(pubkey: PublicKey): array[CompressedPubKeyLength, byte] {
   ## Converts public key `pubkey` to serialized form.
   pubkey.toRaw(result, true)
 
-proc getRaw*(s: Signature): array[RawSignatureSize, byte] {.noinit.} =
-  ## Converts signature `s` to serialized form.
-  let ctx = getSecpContext()
-  var recid = cint(0)
-  if secp256k1_ecdsa_recoverable_signature_serialize_compact(
-    ctx, cast[ptr cuchar](unsafeAddr result), addr recid, unsafeAddr s) != 1:
-    raiseSecp256k1Error()
-  result[64] = uint8(recid)
-
 proc toRaw*(s: Signature, data: var openarray[byte]) =
   ## Converts signature `s` to serialized form and store it in `data`.
   let ctx = getSecpContext()
@@ -274,6 +303,22 @@ proc toRaw*(s: Signature, data: var openarray[byte]) =
     raiseSecp256k1Error()
   data[64] = uint8(recid)
 
+proc getRaw*(s: Signature): array[RawSignatureSize, byte] {.noinit.} =
+  ## Converts signature `s` to serialized form.
+  s.toRaw(result)
+
+proc toRaw*(s: SignatureNR, data: var openarray[byte]) =
+  ## Converts signature `s` to serialized form and store it in `data`.
+  doAssert(len(data) == RawSignatureNRSize)
+  let ctx = getSecpContext()
+  if secp256k1_ecdsa_signature_serialize_compact(ctx, cast[ptr cuchar](addr data[0]),
+                                                 unsafeAddr s) != 1:
+    raiseSecp256k1Error()
+
+proc getRaw*(s: SignatureNR): array[RawSignatureNRSize, byte] {.noinit.} =
+  ## Converts signature `s` to serialized form.
+  s.toRaw(result)
+
 proc recoverSignatureKey*(data: openarray[byte],
                           msg: openarray[byte],
                           pubkey: var PublicKey): EthKeysStatus =
@@ -330,3 +375,34 @@ proc signRawMessage*(data: openarray[byte], seckey: PrivateKey,
     return(EthKeysStatus.Error)
   return(EthKeysStatus.Success)
 
+proc signRawMessage*(data: openarray[byte], seckey: PrivateKey,
+                     signature: var SignatureNR): EthKeysStatus =
+  ## Sign message `data` of `KeyLength` size using private key `seckey` and
+  ## store result into `signature`.
+  let ctx = getSecpContext()
+  let length = len(data)
+  if length != KeyLength:
+    setErrorMsg(MessageSizeError)
+    return(EthKeysStatus.Error)
+  if secp256k1_ecdsa_sign(ctx, addr signature,
+                          cast[ptr cuchar](unsafeAddr data[0]),
+                          cast[ptr cuchar](unsafeAddr seckey),
+                          nil, nil) != 1:
+    return(EthKeysStatus.Error)
+  return(EthKeysStatus.Success)
+
+proc verifySignatureRaw*(signature: SignatureNR, message: openarray[byte],
+                         publicKey: PublicKey): EthKeysStatus =
+  ## Verify `signature` using original `message` (32 bytes) and `publicKey`.
+  let ctx = getSecpContext()
+  if len(message) != KeyLength:
+    setErrorMsg(MessageSizeError)
+    return(EthKeysStatus.Error)
+
+  if secp256k1_ecdsa_verify(ctx, unsafeAddr signature,
+                            cast[ptr cuchar](unsafeAddr message[0]),
+                            unsafeAddr publicKey) != 1:
+    setErrorMsg(VerificationFailed)
+    return(EthKeysStatus.Error)
+
+  return(EthKeysStatus.Success)