diff options
Diffstat (limited to 'src/pubkey/elgamal/elgamal.cpp')
| -rw-r--r-- | src/pubkey/elgamal/elgamal.cpp | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/src/pubkey/elgamal/elgamal.cpp b/src/pubkey/elgamal/elgamal.cpp index fe83b3b2b..b2ffe36f3 100644 --- a/src/pubkey/elgamal/elgamal.cpp +++ b/src/pubkey/elgamal/elgamal.cpp @@ -117,6 +117,9 @@ ElGamal_Decryption_Operation::ElGamal_Decryption_Operation(const ElGamal_Private powermod_x_p = Fixed_Exponent_Power_Mod(key.get_x(), p); mod_p = Modular_Reducer(p); + + BigInt k = Blinder::choose_nonce(key.get_x(), p); + blinder = Blinder(k, power_mod(k, key.get_x(), p), p); } SecureVector<byte> @@ -135,7 +138,11 @@ ElGamal_Decryption_Operation::decrypt(const byte msg[], u32bit msg_len) const if(a >= p || b >= p) throw Invalid_Argument("ElGamal decryption: Invalid message"); - return BigInt::encode(mod_p.multiply(b, inverse_mod(powermod_x_p(a), p))); + a = blinder.blind(a); + + BigInt r = mod_p.multiply(b, inverse_mod(powermod_x_p(a), p)); + + return BigInt::encode(blinder.unblind(r)); } } |