From d66b3ee6993a99e51cc2852b0356c386337a2d5c Mon Sep 17 00:00:00 2001 From: René Korthaus Date: Tue, 1 Mar 2016 18:03:56 +0100 Subject: Add ECGDSA --- src/lib/pubkey/ecgdsa/ecgdsa.cpp | 148 +++++++++++++++++++++++++++++++++++++++ src/lib/pubkey/ecgdsa/ecgdsa.h | 91 ++++++++++++++++++++++++ src/lib/pubkey/ecgdsa/info.txt | 13 ++++ 3 files changed, 252 insertions(+) create mode 100644 src/lib/pubkey/ecgdsa/ecgdsa.cpp create mode 100644 src/lib/pubkey/ecgdsa/ecgdsa.h create mode 100644 src/lib/pubkey/ecgdsa/info.txt (limited to 'src/lib/pubkey/ecgdsa') diff --git a/src/lib/pubkey/ecgdsa/ecgdsa.cpp b/src/lib/pubkey/ecgdsa/ecgdsa.cpp new file mode 100644 index 000000000..b28e3fe96 --- /dev/null +++ b/src/lib/pubkey/ecgdsa/ecgdsa.cpp @@ -0,0 +1,148 @@ +/* +* ECGDSA (BSI-TR-03111, version 2.0) +* (C) 2016 René Korthaus +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include +#include +#include + +namespace Botan { + +bool ECGDSA_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)"); + } + +namespace { + +/** +* ECGDSA signature operation +*/ +class ECGDSA_Signature_Operation : public PK_Ops::Signature_with_EMSA + { + public: + typedef ECGDSA_PrivateKey Key_Type; + + ECGDSA_Signature_Operation(const ECGDSA_PrivateKey& ecgdsa, + const std::string& emsa) : + PK_Ops::Signature_with_EMSA(emsa), + m_order(ecgdsa.domain().get_order()), + m_base_point(ecgdsa.domain().get_base_point(), m_order), + m_x(ecgdsa.private_value()), + m_mod_order(m_order) + { + } + + secure_vector raw_sign(const byte msg[], size_t msg_len, + RandomNumberGenerator& rng) override; + + size_t message_parts() const override { return 2; } + size_t message_part_size() const override { return m_order.bytes(); } + size_t max_input_bits() const override { return m_order.bits(); } + + private: + const BigInt& m_order; + Blinded_Point_Multiply m_base_point; + const BigInt& m_x; + Modular_Reducer m_mod_order; + }; + +secure_vector +ECGDSA_Signature_Operation::raw_sign(const byte msg[], size_t msg_len, + RandomNumberGenerator& rng) + { + const BigInt m(msg, msg_len); + + BigInt k = BigInt::random_integer(rng, 1, m_order); + + const PointGFp k_times_P = m_base_point.blinded_multiply(k, rng); + const BigInt r = m_mod_order.reduce(k_times_P.get_affine_x()); + const BigInt s = m_mod_order.multiply(m_x, mul_sub(k, r, m)); + + // With overwhelming probability, a bug rather than actual zero r/s + BOTAN_ASSERT(s != 0, "invalid s"); + BOTAN_ASSERT(r != 0, "invalid r"); + + secure_vector output(2*m_order.bytes()); + r.binary_encode(&output[output.size() / 2 - r.bytes()]); + s.binary_encode(&output[output.size() - s.bytes()]); + return output; + } + +/** +* ECGDSA verification operation +*/ +class ECGDSA_Verification_Operation : public PK_Ops::Verification_with_EMSA + { + public: + typedef ECGDSA_PublicKey Key_Type; + + ECGDSA_Verification_Operation(const ECGDSA_PublicKey& ecgdsa, + const std::string& emsa) : + PK_Ops::Verification_with_EMSA(emsa), + m_base_point(ecgdsa.domain().get_base_point()), + m_public_point(ecgdsa.public_point()), + m_order(ecgdsa.domain().get_order()), + m_mod_order(m_order) + { + } + + size_t message_parts() const override { return 2; } + size_t message_part_size() const override { return m_order.bytes(); } + size_t max_input_bits() const override { return m_order.bits(); } + + bool with_recovery() const override { return false; } + + bool verify(const byte msg[], size_t msg_len, + const byte sig[], size_t sig_len) override; + private: + const PointGFp& m_base_point; + const PointGFp& m_public_point; + const BigInt& m_order; + // FIXME: should be offered by curve + Modular_Reducer m_mod_order; + }; + +bool ECGDSA_Verification_Operation::verify(const byte msg[], size_t msg_len, + const byte sig[], size_t sig_len) + { + if(sig_len != m_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 >= m_order || s <= 0 || s >= m_order) + return false; + + BigInt w = inverse_mod(r, m_order); + + const BigInt u1 = m_mod_order.reduce(e * w); + const BigInt u2 = m_mod_order.reduce(s * w); + const PointGFp R = multi_exponentiate(m_base_point, u1, m_public_point, u2); + + if(R.is_zero()) + return false; + + const BigInt v = m_mod_order.reduce(R.get_affine_x()); + return (v == r); + } + +BOTAN_REGISTER_PK_SIGNATURE_OP("ECGDSA", ECGDSA_Signature_Operation); +BOTAN_REGISTER_PK_VERIFY_OP("ECGDSA", ECGDSA_Verification_Operation); + +} + +} diff --git a/src/lib/pubkey/ecgdsa/ecgdsa.h b/src/lib/pubkey/ecgdsa/ecgdsa.h new file mode 100644 index 000000000..518adeeab --- /dev/null +++ b/src/lib/pubkey/ecgdsa/ecgdsa.h @@ -0,0 +1,91 @@ +/* +* ECGDSA (BSI-TR-03111, version 2.0) +* (C) 2016 René Korthaus +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#ifndef BOTAN_ECGDSA_KEY_H__ +#define BOTAN_ECGDSA_KEY_H__ + +#include + +namespace Botan { + +/** +* This class represents ECGDSA public keys. +*/ +class BOTAN_DLL ECGDSA_PublicKey : public virtual EC_PublicKey + { + public: + + /** + * Construct a public key from a given public point. + * @param dom_par the domain parameters associated with this key + * @param public_point the public point defining this key + */ + ECGDSA_PublicKey(const EC_Group& dom_par, + const PointGFp& public_point) : + EC_PublicKey(dom_par, public_point) {} + + ECGDSA_PublicKey(const AlgorithmIdentifier& alg_id, + const secure_vector& key_bits) : + EC_PublicKey(alg_id, key_bits) {} + + /** + * Get this keys algorithm name. + * @result this keys algorithm name ("ECGDSA") + */ + std::string algo_name() const override { return "ECGDSA"; } + + /** + * Get the maximum number of bits allowed to be fed to this key. + * This is the bitlength of the order of the base point. + * @result the maximum number of input bits + */ + size_t max_input_bits() const override + { return domain().get_order().bits(); } + + size_t message_parts() const override { return 2; } + + size_t message_part_size() const override + { return domain().get_order().bytes(); } + + protected: + ECGDSA_PublicKey() {} + }; + +/** +* This class represents ECGDSA private keys. +*/ +class BOTAN_DLL ECGDSA_PrivateKey : public ECGDSA_PublicKey, + public EC_PrivateKey + { + public: + + /** + * Load a private key + * @param alg_id the X.509 algorithm identifier + * @param key_bits PKCS #8 structure + */ + ECGDSA_PrivateKey(const AlgorithmIdentifier& alg_id, + const secure_vector& key_bits) : + EC_PrivateKey(alg_id, key_bits, true) {} + + /** + * Generate a new private key + * @param rng a random number generator + * @param domain parameters to used for this key + * @param x the private key (if zero, generate a new random key) + */ + ECGDSA_PrivateKey(RandomNumberGenerator& rng, + const EC_Group& domain, + const BigInt& x = 0) : + EC_PrivateKey(rng, domain, x, true) {} + + bool check_key(RandomNumberGenerator& rng, bool) const override; + }; + +} + +#endif diff --git a/src/lib/pubkey/ecgdsa/info.txt b/src/lib/pubkey/ecgdsa/info.txt new file mode 100644 index 000000000..9583c47d4 --- /dev/null +++ b/src/lib/pubkey/ecgdsa/info.txt @@ -0,0 +1,13 @@ +define ECGDSA 20160301 + +load_on request + + +asn1 +bigint +ec_group +ecc_key +keypair +numbertheory +rng + -- cgit v1.2.3