i2pd/libi2pd/Signature.cpp
2018-06-05 12:53:13 -04:00

58 lines
1.9 KiB
C++

#include <memory>
#include "Log.h"
#include "Signature.h"
namespace i2p
{
namespace crypto
{
EDDSA25519Verifier::EDDSA25519Verifier (const uint8_t * signingKey)
{
memcpy (m_PublicKeyEncoded, signingKey, EDDSA25519_PUBLIC_KEY_LENGTH);
BN_CTX * ctx = BN_CTX_new ();
m_PublicKey = GetEd25519 ()->DecodePublicKey (m_PublicKeyEncoded, ctx);
BN_CTX_free (ctx);
}
bool EDDSA25519Verifier::Verify (const uint8_t * buf, size_t len, const uint8_t * signature) const
{
uint8_t digest[64];
SHA512_CTX ctx;
SHA512_Init (&ctx);
SHA512_Update (&ctx, signature, EDDSA25519_SIGNATURE_LENGTH/2); // R
SHA512_Update (&ctx, m_PublicKeyEncoded, EDDSA25519_PUBLIC_KEY_LENGTH); // public key
SHA512_Update (&ctx, buf, len); // data
SHA512_Final (digest, &ctx);
return GetEd25519 ()->Verify (m_PublicKey, digest, signature);
}
EDDSA25519Signer::EDDSA25519Signer (const uint8_t * signingPrivateKey, const uint8_t * signingPublicKey)
{
// expand key
Ed25519::ExpandPrivateKey (signingPrivateKey, m_ExpandedPrivateKey);
// generate and encode public key
BN_CTX * ctx = BN_CTX_new ();
auto publicKey = GetEd25519 ()->GeneratePublicKey (m_ExpandedPrivateKey, ctx);
GetEd25519 ()->EncodePublicKey (publicKey, m_PublicKeyEncoded, ctx);
if (signingPublicKey && memcmp (m_PublicKeyEncoded, signingPublicKey, EDDSA25519_PUBLIC_KEY_LENGTH))
{
// keys don't match, it means older key with 0x1F
LogPrint (eLogWarning, "Older EdDSA key detected");
m_ExpandedPrivateKey[EDDSA25519_PRIVATE_KEY_LENGTH - 1] &= 0xDF; // drop third bit
publicKey = GetEd25519 ()->GeneratePublicKey (m_ExpandedPrivateKey, ctx);
GetEd25519 ()->EncodePublicKey (publicKey, m_PublicKeyEncoded, ctx);
}
BN_CTX_free (ctx);
}
void EDDSA25519Signer::Sign (const uint8_t * buf, int len, uint8_t * signature) const
{
GetEd25519 ()->Sign (m_ExpandedPrivateKey, m_PublicKeyEncoded, buf, len, signature);
}
}
}