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81 lines
2.1 KiB
81 lines
2.1 KiB
/*
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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 "AES.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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/// Public key of remote and corresponding shared secret.
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using AliasSession = std::pair<Public,h256>;
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/**
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* @brief An addressable EC key pair.
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*/
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class Alias
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{
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public:
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Alias(Secret const& _s): m_secret(_s) {};
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AliasSession session(Address _a) { return m_sessions.count(_a) ? m_sessions.find(_a)->second : AliasSession(); }
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private:
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std::map<Address,AliasSession> m_sessions;
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Secret m_secret;
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};
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namespace ecdh
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{
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void agree(Secret const& _s, Public const& _r, Secret& o_s);
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}
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/**
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* @brief Derive DH shared secret from EC keypairs.
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* As ephemeral keys are single-use, agreement is limited to a single occurence.
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*/
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class ECDHE
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{
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public:
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/// Constructor (pass public key for ingress exchange).
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ECDHE(): m_ephemeral(KeyPair::create()) {};
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/// Public key sent to remote.
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Public pubkey() { return m_ephemeral.pub(); }
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Secret seckey() { return m_ephemeral.sec(); }
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/// Input public key for dh agreement, output generated shared secret.
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void agree(Public const& _remoteEphemeral, Secret& o_sharedSecret) const;
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protected:
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KeyPair m_ephemeral; ///< Ephemeral keypair; generated.
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mutable Public m_remoteEphemeral; ///< Public key of remote; parameter. Set once when agree is called, otherwise immutable.
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};
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}
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}
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