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Diffstat (limited to '')
-rw-r--r-- | comm/third_party/botan/src/lib/pubkey/dh/dh.cpp | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pubkey/dh/dh.cpp b/comm/third_party/botan/src/lib/pubkey/dh/dh.cpp new file mode 100644 index 0000000000..687032a696 --- /dev/null +++ b/comm/third_party/botan/src/lib/pubkey/dh/dh.cpp @@ -0,0 +1,142 @@ +/* +* Diffie-Hellman +* (C) 1999-2007,2016,2019 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/dh.h> +#include <botan/internal/pk_ops_impl.h> +#include <botan/internal/monty_exp.h> +#include <botan/blinding.h> + +namespace Botan { + +/* +* DH_PublicKey Constructor +*/ +DH_PublicKey::DH_PublicKey(const DL_Group& grp, const BigInt& y1) + { + m_group = grp; + m_y = y1; + } + +/* +* Return the public value for key agreement +*/ +std::vector<uint8_t> DH_PublicKey::public_value() const + { + return unlock(BigInt::encode_1363(m_y, group_p().bytes())); + } + +/* +* Create a DH private key +*/ +DH_PrivateKey::DH_PrivateKey(RandomNumberGenerator& rng, + const DL_Group& grp, + const BigInt& x_arg) + { + m_group = grp; + + if(x_arg == 0) + { + const size_t exp_bits = grp.exponent_bits(); + m_x.randomize(rng, exp_bits); + m_y = m_group.power_g_p(m_x, exp_bits); + } + else + { + m_x = x_arg; + + if(m_y == 0) + m_y = m_group.power_g_p(m_x, grp.p_bits()); + } + } + +/* +* Load a DH private key +*/ +DH_PrivateKey::DH_PrivateKey(const AlgorithmIdentifier& alg_id, + const secure_vector<uint8_t>& key_bits) : + DL_Scheme_PrivateKey(alg_id, key_bits, DL_Group::ANSI_X9_42) + { + if(m_y.is_zero()) + { + m_y = m_group.power_g_p(m_x, m_group.p_bits()); + } + } + +/* +* Return the public value for key agreement +*/ +std::vector<uint8_t> DH_PrivateKey::public_value() const + { + return DH_PublicKey::public_value(); + } + +namespace { + +/** +* DH operation +*/ +class DH_KA_Operation final : public PK_Ops::Key_Agreement_with_KDF + { + public: + + DH_KA_Operation(const DH_PrivateKey& key, const std::string& kdf, RandomNumberGenerator& rng) : + PK_Ops::Key_Agreement_with_KDF(kdf), + m_p(key.group_p()), + m_x(key.get_x()), + m_x_bits(m_x.bits()), + m_monty_p(key.get_group().monty_params_p()), + m_blinder(m_p, + rng, + [](const BigInt& k) { return k; }, + [this](const BigInt& k) { return powermod_x_p(inverse_mod(k, m_p)); }) + {} + + size_t agreed_value_size() const override { return m_p.bytes(); } + + secure_vector<uint8_t> raw_agree(const uint8_t w[], size_t w_len) override; + private: + BigInt powermod_x_p(const BigInt& v) const + { + const size_t powm_window = 4; + auto powm_v_p = monty_precompute(m_monty_p, v, powm_window); + return monty_execute(*powm_v_p, m_x, m_x_bits); + } + + const BigInt& m_p; + const BigInt& m_x; + const size_t m_x_bits; + std::shared_ptr<const Montgomery_Params> m_monty_p; + Blinder m_blinder; + }; + +secure_vector<uint8_t> DH_KA_Operation::raw_agree(const uint8_t w[], size_t w_len) + { + BigInt v = BigInt::decode(w, w_len); + + if(v <= 1 || v >= m_p - 1) + throw Invalid_Argument("DH agreement - invalid key provided"); + + v = m_blinder.blind(v); + v = powermod_x_p(v); + v = m_blinder.unblind(v); + + return BigInt::encode_1363(v, m_p.bytes()); + } + +} + +std::unique_ptr<PK_Ops::Key_Agreement> +DH_PrivateKey::create_key_agreement_op(RandomNumberGenerator& rng, + const std::string& params, + const std::string& provider) const + { + if(provider == "base" || provider.empty()) + return std::unique_ptr<PK_Ops::Key_Agreement>(new DH_KA_Operation(*this, params, rng)); + throw Provider_Not_Found(algo_name(), provider); + } + +} |