Some fixes and tests for ECIES.

ethp2p/auth.nim

@@ -26,6 +26,18 @@ const
   AuthAckMessageLength* = 210
 
 type
+  PlainAuthMessage* = object {.packed.}
+    signature: RawSignature
+    keyhash: array[keccak256.sizeDigest, byte]
+    pubkey: PublicKey
+    nonce: array[keccak256.sizeDigest, byte]
+    flag: byte
+
+  PlainAuthAckMessage* = object {.packed.}
+    pubkey: PublicKey
+    nonce: array[keccak256.sizeDigest, byte]
+    flag: byte
+
   HandshakeFlag* = enum
     Initiator,      ## `Handshake` owner is connection initiator
     Responder,      ## `Handshake` owner is connection responder
@@ -62,8 +74,8 @@ type
     egressMac*: array[keccak256.sizeDigest, byte]
     ingressMac*: array[keccak256.sizeDigest, byte]
 
-  PlainAuthMessage* = array[PlainAuthMessageLength, byte]
-  PlainAuthAckMessage* = array[PlainAuthAckMessageLength, byte]
+  # PlainAuthMessage* = array[PlainAuthMessageLength, byte]
+  # PlainAuthAckMessage* = array[PlainAuthAckMessageLength, byte]
   AuthMessage* = array[AuthMessageLength, byte]
   AuthAckMessage* = array[AuthAckMessageLength, byte]
 
@@ -95,50 +107,44 @@ proc newHandshake*(flags: set[HandshakeFlag] = {Initiator}): Handshake =
   result.ephemeral = newKeyPair()
 
   if Initiator in flags:
-    p = addr result.initiatorNonce[0]
+    if randomBytes(result.initiatorNonce) != len(result.initiatorNonce):
+      raise newException(AuthException, "Could not obtain random data!")
   else:
-    p = addr result.responderNonce[0]
-
-  if randomBytes(p, KeyLength) != KeyLength:
+    if randomBytes(result.responderNonce) != len(result.responderNonce):
       raise newException(AuthException, "Could not obtain random data!")
 
-proc authMessage*(h: var Handshake,
+proc authMessagePreEIP8*(h: var Handshake,
                   pubkey: PublicKey,
-                  output: var PlainAuthMessage): AuthStatus =
+                  output: var PlainAuthMessage,
+                  flag: int = 0): AuthStatus =
   ## Create plain preEIP8 authentication message.
   var secret: SharedSecret
   var signature: Signature
-  var flag = byte(0x00)
+  var flagb = byte(flag)
 
   if ecdhAgree(h.host.seckey, pubkey, secret) != EccStatus.Success:
     return(EcdhError)
 
-  if h.initiatorNonce.empty():
-    if randomBytes(addr h.initiatorNonce[0], KeyLength) != KeyLength:
-      return(RandomError)
-
   var xornonce = h.initiatorNonce
   xornonce.sxor(secret)
 
   if signMessage(h.ephemeral.seckey, xornonce, signature) != EccStatus.Success:
     return(SignatureError)
 
-  copyMem(addr h.remoteHPubkey, unsafeAddr pubkey, sizeof(PublicKey))
+  h.remoteHPubkey = pubkey
   
-  move(output, signature.getRaw().data, 0, 64)
-  move(output, keccak256.digest(h.ephemeral.pubkey.getRaw().data).data, 65, 96)
-  move(output, h.host.pubkey.getRaw().data, 97, 160)
-  move(output, h.initiatorNonce, 161, 192)
-  output[193] = flag
+  output.signature = signature.getRaw()
+  output.keyhash = keccak256.digest(h.ephemeral.pubkey.getRaw().data).data
+  output.pubkey = cast[PublicKey](h.host.pubkey.getRaw().data)
+  output.nonce = h.initiatorNonce
+  output.flag = flagb
 
-proc authAckMessage*(h: var Handshake,
-                     output: var PlainAuthAckMessage): AuthStatus =
-  if EIP8 in h.flags:
-    discard
-  else:
-    move(output, h.ephemeral.pubkey.getRaw().data, 0, 63)
-    move(output, h.responderNonce, 64, 95)
-    output[96] = byte(0x00)
+proc authAckMessagePreEIP8*(h: var Handshake,
+                            output: var PlainAuthAckMessage,
+                            flag: int = 0): AuthStatus =
+  output.pubkey = cast[PublicKey](h.ephemeral.pubkey.getRaw().data)
+  output.nonce = h.responderNonce
+  output.flag = byte(flag)
 
 proc encryptAuthMessage*(input: ptr byte, inputlen: int,
                          output: ptr byte, outputlen: int,

ethp2p/ecc.nim

@@ -16,7 +16,6 @@ const
   PublicKeyLength* = 64
   SignatureLength* = 65
 
-
 type
   EccContext* = ref object of RootRef
     context*: ptr secp256k1_context
@@ -264,7 +263,7 @@ proc newPrivateKey*(): PrivateKey =
   ## Generates new secret key.
   let ctx = getSecpContext()
   while true:
-    if randomBytes(addr result[0], KeyLength) == KeyLength:
+    if randomBytes(result) == KeyLength:
       if secp256k1_ec_seckey_verify(ctx, cast[ptr cuchar](addr result[0])) == 1:
         break
 

ethp2p/ecies.nim

@@ -166,7 +166,7 @@ proc eciesDecrypt*(input: openarray[byte],
     ctx: HMAC[sha256]
     secret: SharedSecret
 
-  if len(input) == 0:
+  if len(input) <= 0:
     return(IncompleteError)
 
   var header = cast[ptr EciesHeader](unsafeAddr input[0])
@@ -188,7 +188,6 @@ proc eciesDecrypt*(input: openarray[byte],
   burnMem(material)
 
   let macsize = eciesMacLength(len(input) - eciesOverheadLength())
-  let datsize = eciesDecryptedLength(len(input))
   ctx.init(macKey.data)
   burnMem(macKey)
   ctx.update(toOpenArray(input, eciesIvPos(), eciesIvPos() + macsize - 1))
@@ -201,6 +200,7 @@ proc eciesDecrypt*(input: openarray[byte],
                   sha256.sizeDigest):
     return(IncorrectTag)
 
+  let datsize = eciesDecryptedLength(len(input))
   cipher.init(encKey, header.iv)
   burnMem(encKey)
   cipher.decrypt(toOpenArray(input, eciesDataPos(),

tests/testecies.nim

@@ -9,7 +9,7 @@
 
 import unittest
 import ethp2p/ecc, ethp2p/ecies
-import nimcrypto/utils, nimcrypto/sha2, nimcrypto/hmac
+import nimcrypto/utils, nimcrypto/sha2, nimcrypto/hmac, nimcrypto/rijndael
 
 proc compare[A, B](x: openarray[A], y: openarray[B], s: int = 0): bool =
   result = true
@@ -20,7 +20,19 @@ proc compare[A, B](x: openarray[A], y: openarray[B], s: int = 0): bool =
       result = false
       break
 
+template offsetOf(a, b): int =
+  cast[int](cast[uint](unsafeAddr b) - cast[uint](unsafeAddr a))
+
 suite "ECIES test suite":
+  test "ECIES structures alignment":
+    var header: EciesHeader
+    check:
+      offsetOf(header, header.version) == 0
+      offsetOf(header, header.pubkey) == 1
+      offsetOf(header, header.iv) == 1 + 64
+      offsetOf(header, header.data) == 1 + 64 + aes128.sizeBlock
+      sizeof(header) == 1 + 64 + aes128.sizeBlock + 1
+
   test "KDF test vectors":
     # KDF test
     # Copied from https://github.com/ethereum/pydevp2p/blob/develop/devp2p/tests/test_ecies.py#L53