diff options
author | lloyd <[email protected]> | 2014-01-10 03:41:59 +0000 |
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committer | lloyd <[email protected]> | 2014-01-10 03:41:59 +0000 |
commit | 6894dca64c04936d07048c0e8cbf7e25858548c3 (patch) | |
tree | 5d572bfde9fe667dab14e3f04b5285a85d8acd95 /src/lib/pubkey/ecdsa/ecdsa.cpp | |
parent | 9efa3be92442afb3d0b69890a36c7f122df18eda (diff) |
Move lib into src
Diffstat (limited to 'src/lib/pubkey/ecdsa/ecdsa.cpp')
-rw-r--r-- | src/lib/pubkey/ecdsa/ecdsa.cpp | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/src/lib/pubkey/ecdsa/ecdsa.cpp b/src/lib/pubkey/ecdsa/ecdsa.cpp new file mode 100644 index 000000000..6ff082649 --- /dev/null +++ b/src/lib/pubkey/ecdsa/ecdsa.cpp @@ -0,0 +1,97 @@ +/* +* ECDSA implemenation +* (C) 2007 Manuel Hartl, FlexSecure GmbH +* 2007 Falko Strenzke, FlexSecure GmbH +* 2008-2010 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#include <botan/ecdsa.h> +#include <botan/keypair.h> + +namespace Botan { + +bool ECDSA_PrivateKey::check_key(RandomNumberGenerator& rng, + bool strong) const + { + if(!public_point().on_the_curve()) + return false; + + if(!strong) + return true; + + return KeyPair::signature_consistency_check(rng, *this, "EMSA1(SHA-1)"); + } + +ECDSA_Signature_Operation::ECDSA_Signature_Operation(const ECDSA_PrivateKey& ecdsa) : + base_point(ecdsa.domain().get_base_point()), + order(ecdsa.domain().get_order()), + x(ecdsa.private_value()), + mod_order(order) + { + } + +secure_vector<byte> +ECDSA_Signature_Operation::sign(const byte msg[], size_t msg_len, + RandomNumberGenerator& rng) + { + rng.add_entropy(msg, msg_len); + + BigInt m(msg, msg_len); + + BigInt r = 0, s = 0; + + while(r == 0 || s == 0) + { + // This contortion is necessary for the tests + BigInt k; + k.randomize(rng, order.bits()); + + while(k >= order) + k.randomize(rng, order.bits() - 1); + + PointGFp k_times_P = base_point * k; + r = mod_order.reduce(k_times_P.get_affine_x()); + s = mod_order.multiply(inverse_mod(k, order), mul_add(x, r, m)); + } + + secure_vector<byte> output(2*order.bytes()); + r.binary_encode(&output[output.size() / 2 - r.bytes()]); + s.binary_encode(&output[output.size() - s.bytes()]); + return output; + } + +ECDSA_Verification_Operation::ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa) : + base_point(ecdsa.domain().get_base_point()), + public_point(ecdsa.public_point()), + order(ecdsa.domain().get_order()) + { + } + +bool ECDSA_Verification_Operation::verify(const byte msg[], size_t msg_len, + const byte sig[], size_t sig_len) + { + if(sig_len != order.bytes()*2) + return false; + + BigInt e(msg, msg_len); + + BigInt r(sig, sig_len / 2); + BigInt s(sig + sig_len / 2, sig_len / 2); + + if(r <= 0 || r >= order || s <= 0 || s >= order) + return false; + + BigInt w = inverse_mod(s, order); + + PointGFp R = w * multi_exponentiate(base_point, e, + public_point, r); + + if(R.is_zero()) + return false; + + return (R.get_affine_x() % order == r); + } + +} |