diff options
Diffstat (limited to 'comm/third_party/botan/src/lib/pubkey/eckcdsa/eckcdsa.cpp')
| -rw-r--r-- | comm/third_party/botan/src/lib/pubkey/eckcdsa/eckcdsa.cpp | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pubkey/eckcdsa/eckcdsa.cpp b/comm/third_party/botan/src/lib/pubkey/eckcdsa/eckcdsa.cpp new file mode 100644 index 0000000000..40d9425143 --- /dev/null +++ b/comm/third_party/botan/src/lib/pubkey/eckcdsa/eckcdsa.cpp @@ -0,0 +1,208 @@ +/* +* ECKCDSA (ISO/IEC 14888-3:2006/Cor.2:2009) +* (C) 2016 René Korthaus, Sirrix AG +* (C) 2018 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/eckcdsa.h> +#include <botan/internal/pk_ops_impl.h> +#include <botan/internal/point_mul.h> +#include <botan/keypair.h> +#include <botan/reducer.h> +#include <botan/emsa.h> +#include <botan/hash.h> +#include <botan/rng.h> + +namespace Botan { + +bool ECKCDSA_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-256)"); + } + +namespace { + +/** +* ECKCDSA signature operation +*/ +class ECKCDSA_Signature_Operation final : public PK_Ops::Signature_with_EMSA + { + public: + + ECKCDSA_Signature_Operation(const ECKCDSA_PrivateKey& eckcdsa, + const std::string& emsa) : + PK_Ops::Signature_with_EMSA(emsa), + m_group(eckcdsa.domain()), + m_x(eckcdsa.private_value()), + m_prefix() + { + const BigInt public_point_x = eckcdsa.public_point().get_affine_x(); + const BigInt public_point_y = eckcdsa.public_point().get_affine_y(); + + m_prefix.resize(public_point_x.bytes() + public_point_y.bytes()); + public_point_x.binary_encode(m_prefix.data()); + public_point_y.binary_encode(&m_prefix[public_point_x.bytes()]); + m_prefix.resize(HashFunction::create(hash_for_signature())->hash_block_size()); // use only the "hash input block size" leftmost bits + } + + secure_vector<uint8_t> raw_sign(const uint8_t msg[], size_t msg_len, + RandomNumberGenerator& rng) override; + + size_t signature_length() const override { return 2*m_group.get_order_bytes(); } + size_t max_input_bits() const override { return m_group.get_order_bits(); } + + bool has_prefix() override { return true; } + secure_vector<uint8_t> message_prefix() const override { return m_prefix; } + + private: + const EC_Group m_group; + const BigInt& m_x; + secure_vector<uint8_t> m_prefix; + std::vector<BigInt> m_ws; + }; + +secure_vector<uint8_t> +ECKCDSA_Signature_Operation::raw_sign(const uint8_t msg[], size_t, + RandomNumberGenerator& rng) + { + const BigInt k = m_group.random_scalar(rng); + const BigInt k_times_P_x = m_group.blinded_base_point_multiply_x(k, rng, m_ws); + + secure_vector<uint8_t> to_be_hashed(k_times_P_x.bytes()); + k_times_P_x.binary_encode(to_be_hashed.data()); + + std::unique_ptr<EMSA> emsa = this->clone_emsa(); + emsa->update(to_be_hashed.data(), to_be_hashed.size()); + secure_vector<uint8_t> c = emsa->raw_data(); + c = emsa->encoding_of(c, max_input_bits(), rng); + + const BigInt r(c.data(), c.size()); + + xor_buf(c, msg, c.size()); + BigInt w(c.data(), c.size()); + w = m_group.mod_order(w); + + const BigInt s = m_group.multiply_mod_order(m_x, k - w); + if(s.is_zero()) + throw Internal_Error("During ECKCDSA signature generation created zero s"); + + secure_vector<uint8_t> output = BigInt::encode_1363(r, c.size()); + output += BigInt::encode_1363(s, m_group.get_order_bytes()); + return output; + } + +/** +* ECKCDSA verification operation +*/ +class ECKCDSA_Verification_Operation final : public PK_Ops::Verification_with_EMSA + { + public: + + ECKCDSA_Verification_Operation(const ECKCDSA_PublicKey& eckcdsa, + const std::string& emsa) : + PK_Ops::Verification_with_EMSA(emsa), + m_group(eckcdsa.domain()), + m_gy_mul(m_group.get_base_point(), eckcdsa.public_point()), + m_prefix() + { + const BigInt public_point_x = eckcdsa.public_point().get_affine_x(); + const BigInt public_point_y = eckcdsa.public_point().get_affine_y(); + + m_prefix.resize(public_point_x.bytes() + public_point_y.bytes()); + public_point_x.binary_encode(&m_prefix[0]); + public_point_y.binary_encode(&m_prefix[public_point_x.bytes()]); + m_prefix.resize(HashFunction::create(hash_for_signature())->hash_block_size()); // use only the "hash input block size" leftmost bits + } + + bool has_prefix() override { return true; } + secure_vector<uint8_t> message_prefix() const override { return m_prefix; } + + size_t max_input_bits() const override { return m_group.get_order_bits(); } + + bool with_recovery() const override { return false; } + + bool verify(const uint8_t msg[], size_t msg_len, + const uint8_t sig[], size_t sig_len) override; + private: + const EC_Group m_group; + const PointGFp_Multi_Point_Precompute m_gy_mul; + secure_vector<uint8_t> m_prefix; + }; + +bool ECKCDSA_Verification_Operation::verify(const uint8_t msg[], size_t, + const uint8_t sig[], size_t sig_len) + { + const std::unique_ptr<HashFunction> hash = HashFunction::create(hash_for_signature()); + //calculate size of r + + const size_t order_bytes = m_group.get_order_bytes(); + + const size_t size_r = std::min(hash -> output_length(), order_bytes); + if(sig_len != size_r + order_bytes) + { + return false; + } + + secure_vector<uint8_t> r(sig, sig + size_r); + + // check that 0 < s < q + const BigInt s(sig + size_r, order_bytes); + + if(s <= 0 || s >= m_group.get_order()) + { + return false; + } + + secure_vector<uint8_t> r_xor_e(r); + xor_buf(r_xor_e, msg, r.size()); + BigInt w(r_xor_e.data(), r_xor_e.size()); + w = m_group.mod_order(w); + + const PointGFp q = m_gy_mul.multi_exp(w, s); + const BigInt q_x = q.get_affine_x(); + secure_vector<uint8_t> c(q_x.bytes()); + q_x.binary_encode(c.data()); + std::unique_ptr<EMSA> emsa = this->clone_emsa(); + emsa->update(c.data(), c.size()); + secure_vector<uint8_t> v = emsa->raw_data(); + Null_RNG rng; + v = emsa->encoding_of(v, max_input_bits(), rng); + + return (v == r); + } + +} + +std::unique_ptr<PK_Ops::Verification> +ECKCDSA_PublicKey::create_verification_op(const std::string& params, + const std::string& provider) const + { + if(provider == "base" || provider.empty()) + return std::unique_ptr<PK_Ops::Verification>(new ECKCDSA_Verification_Operation(*this, params)); + throw Provider_Not_Found(algo_name(), provider); + } + +std::unique_ptr<PK_Ops::Signature> +ECKCDSA_PrivateKey::create_signature_op(RandomNumberGenerator& /*rng*/, + const std::string& params, + const std::string& provider) const + { + if(provider == "base" || provider.empty()) + return std::unique_ptr<PK_Ops::Signature>(new ECKCDSA_Signature_Operation(*this, params)); + throw Provider_Not_Found(algo_name(), provider); + } + +} |