/************************************************* * Diffie-Hellman Source File * * (C) 1999-2007 Jack Lloyd * *************************************************/ #include #include #include namespace Botan { /************************************************* * DH_PublicKey Constructor * *************************************************/ DH_PublicKey::DH_PublicKey(const DL_Group& grp, const BigInt& y1) { group = grp; y = y1; X509_load_hook(); } /************************************************* * Algorithm Specific X.509 Initialization Code * *************************************************/ void DH_PublicKey::X509_load_hook() { load_check(); } /************************************************* * Return the maximum input size in bits * *************************************************/ u32bit DH_PublicKey::max_input_bits() const { return group_p().bits(); } /************************************************* * Return the public value for key agreement * *************************************************/ MemoryVector DH_PublicKey::public_value() const { return BigInt::encode_1363(y, group_p().bytes()); } /************************************************* * Create a DH private key * *************************************************/ DH_PrivateKey::DH_PrivateKey(const DL_Group& grp) { group = grp; const BigInt& p = group_p(); x = random_integer(2 * dl_work_factor(p.bits())); PKCS8_load_hook(true); } /************************************************* * DH_PrivateKey Constructor * *************************************************/ DH_PrivateKey::DH_PrivateKey(const DL_Group& grp, const BigInt& x1, const BigInt& y1) { group = grp; y = y1; x = x1; PKCS8_load_hook(); } /************************************************* * Algorithm Specific PKCS #8 Initialization Code * *************************************************/ void DH_PrivateKey::PKCS8_load_hook(bool generated) { if(y == 0) y = power_mod(group_g(), x, group_p()); core = DH_Core(group, x); if(generated) gen_check(); else load_check(); } /************************************************* * Return the public value for key agreement * *************************************************/ MemoryVector DH_PrivateKey::public_value() const { return DH_PublicKey::public_value(); } /************************************************* * Derive a key * *************************************************/ SecureVector DH_PrivateKey::derive_key(const byte w[], u32bit w_len) const { return derive_key(BigInt::decode(w, w_len)); } /************************************************* * Derive a key * *************************************************/ SecureVector DH_PrivateKey::derive_key(const DH_PublicKey& key) const { return derive_key(key.get_y()); } /************************************************* * Derive a key * *************************************************/ SecureVector DH_PrivateKey::derive_key(const BigInt& w) const { const BigInt& p = group_p(); if(w <= 1 || w >= p-1) throw Invalid_Argument(algo_name() + "::derive_key: Invalid key input"); return BigInt::encode_1363(core.agree(w), p.bytes()); } }