#Bitcoin signature malformed base64 encoding how to#
#Bitcoin signature malformed base64 encoding code#

#Bitcoin signature malformed base64 encoding code#

This answer says there are 4 possible public keys that can produce a signature, and this is encoded in the newer signatures.Īfter referencing BitcoinJ, it appears some of these code samples are missing proper preparation of the message, double-SHA256 hashing, and possible compressed encoding of the recovered public point that is input to the address calculation. the code for ECDSA_SIG_recover_key_GFp is here (the signature is a valid signature of the given data for that key)īool Recover(const uint256 &hash, const unsigned char *p64, int rec)īool ret = ECDSA_SIG_recover_key_GFp(pkey, sig, (unsigned char*)&hash, sizeof(hash), rec, 0) = 1 If this function succeeds, the recovered public key is guaranteed to be valid This is only slightly more CPU intensive than just verifying it. reconstruct public key from a compact signature This is the C++ code that I think I need in C#, ideally in bouncy castle. I'm not a C++ programmer so I'm assuming I need to figure out how key.Recover works. THIS is the Bitcoin source that verifies a message.Īfter decoding the Base64 of the signature, the RecoverCompact(hash of message, signature) is called. Return signer.VerifySignature(signature)

Signer.BlockUpdate(plainTextAsBytes, 0, plainTextAsBytes.Length)

Var signer = SignerUtilities.GetSigner('ECDSA') // possibly similar to SHA-1withECDSA PublicKey pubKey = f.generatePublic(pubKeySpec) In the sample below Q is the hard coded value Org.Bounc圜9.X9ECParameters ecp = Org.Bounc圜.GetByName('secp256k1') ĮCDomainParameters params = new ECDomainParameters(ecp.Curve, ecp.G, ecp.N, ecp.H) ĮCPublicKeySpec pubKeySpec = new ECPublicKeySpec(Įcp.

#Bitcoin signature malformed base64 encoding how to#

This link describes how to use ECDSA curves, and the following code will allow me to convert a public key into a BC object, but I'm unsure on how to get the point Q from the signature. What is the correct way to verify the signature? (assume that I already know how to convert the Public Key bits into a hash that equals the Bitcoin hash above) How do I extract the public key in Bouncy Castle? In the Signature above, what format is this signature in? PKCS10? (Answer: no, it's proprietary as described here) I don't need assistance in doing this, I just need help in extracting the public key bits and verifying the signature. If I want to (and I actually do want to) I should be able to convert these public key bits into the Base58 hash. However, it is possible to extract the public key from a signature.Įdit: I'm emphasizing that I'm deriving the Public key from the signature itself, and not from the Base58 public key hash. Since the Base58 Bitcoin address is just a hash, I can't use it for validation of a Bitcoin message. Signature IB7XjSi9TdBbB3dVUK4+Uzqf2Pqk71XkZ5PUsVUN+2gnb3TaZWJwWW2jt0OjhHc4B++yYYRy1Lg2kl+WaiF+Xsc=īase58 Bitcoin address 'hash' 1Kb76YK9a4mhrif766m321AMocNvzeQxqV

My problem is: How do I extract the key from the signature? (Edit I found the c++ code at the bottom of this post, need it in Bouncy Castle / or C#) I intend to extract the key from the signature, hash that key, and compare the Base58 hashes. I have the following message, signature, and Base58 address below. It seems to have a problem with actually coming up with the correct Base 58 address. There is something wrong in the C# implementation that I can probably correct from this Python implementation Please note that the message to be verified must have Bitcoin Signed Message: as a prefix. Update: Partial solution available on GitĮDIT: A compiled version of this is available at