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98 lines
2.9 KiB
98 lines
2.9 KiB
10 years ago
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/*
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This file is part of cpp-ethereum.
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cpp-ethereum is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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cpp-ethereum is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file ECDHE.h
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* @author Alex Leverington <nessence@gmail.com>
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* @date 2014
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*
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* Elliptic curve Diffie-Hellman ephemeral key exchange
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*/
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#pragma once
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#include "EC.h"
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namespace dev
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{
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namespace crypto
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{
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/**
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* @brief Derive DH shared secret from EC keypairs.
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* @todo shield secret()
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*/
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class ECDHE
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{
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friend class ECDHETKeyExchange;
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public:
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ECDHE();
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/// Agree on ECDH parmaters and derive shared secret.
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void agree(Public _remote);
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protected:
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Secret secret();
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private:
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KeyPair m_ephemeral; ///< Ephemeral keypair
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Public m_remote; ///< Public key of remote
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};
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/**
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* @brief Secure exchange of static keys.
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* Key exchange is encrypted with public key of remote and then encrypted by block cipher. For a blind remote the ecdhe public key is used to encrypt exchange, and for a trusted remote the trusted public key is used. The block cipher key is derived from ecdhe shared secret.
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*/
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class ECDHETKeyExchange
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{
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public:
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/// Blind key exchange. KeyPair trusts will be updated if successful.
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ECDHETKeyExchange(ECDHE const& _ecdhe, ECKeyPair* _keyTrust);
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/// Trusted key exchange. Upon success, KeyPair trusts will be updated.
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ECDHETKeyExchange(ECDHE const& _ecdhe, ECKeyPair* _keyTrust, Address _remote);
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/// Authentication for trusted remote, blind trust, or disconnect.
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/// @returns key exchange. encrypted w/aes-ctr. key=ecdhe.m_shared[0-127]
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/// If blind, plaintext is:
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/// sha3(newPublicKey) ||
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/// e(ecdhe.m_remote,sha3(dhe-k)||sign(m_auth.sec,sha3(m))||m)||mac
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/// If trusted, plaintext is:
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/// sha3(previous ecdsa k) || // trust.second
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/// e(m_trusted,sha3(dhe-k)||sign(m_auth.sec,sha3(m))||m)||mac
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/// bytes is encrypted via aes-ctr with ecdhe-derived secret.
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bytes exchange();
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/// Decrypts payload, checks mac, checks trust, decrypts exchange, authenticates exchange, verifies version, verifies signature, and if no failures occur, updates or creats trust and derives trusted-shared-secret.
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bytes authenticate(bytes _exchangeIn);
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/// Encrypts message; @returns e(k,m).
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void encrypt();
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/// Signs message then encrypts; @returns e(k,sign(k,sha3(m))||m).
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bytes signEncrypt(bytes _m);
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private:
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bool blind;
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ECDHE const& m_ecdhe;
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ECKeyPair* m_keypair;
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PublicTrust m_trust;
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};
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}
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}
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