mirror of https://github.com/bitcoin/bitcoin
97 lines
3.9 KiB
C++
97 lines
3.9 KiB
C++
// Copyright (c) 2023 The Bitcoin Core developers
|
|
// Distributed under the MIT software license, see the accompanying
|
|
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
|
|
|
#ifndef BITCOIN_BIP324_H
|
|
#define BITCOIN_BIP324_H
|
|
|
|
#include <array>
|
|
#include <cstddef>
|
|
#include <optional>
|
|
|
|
#include <crypto/chacha20.h>
|
|
#include <crypto/chacha20poly1305.h>
|
|
#include <key.h>
|
|
#include <pubkey.h>
|
|
#include <span.h>
|
|
|
|
/** The BIP324 packet cipher, encapsulating its key derivation, stream cipher, and AEAD. */
|
|
class BIP324Cipher
|
|
{
|
|
public:
|
|
static constexpr unsigned SESSION_ID_LEN{32};
|
|
static constexpr unsigned GARBAGE_TERMINATOR_LEN{16};
|
|
static constexpr unsigned REKEY_INTERVAL{224};
|
|
static constexpr unsigned LENGTH_LEN{3};
|
|
static constexpr unsigned HEADER_LEN{1};
|
|
static constexpr unsigned EXPANSION = LENGTH_LEN + HEADER_LEN + FSChaCha20Poly1305::EXPANSION;
|
|
static constexpr std::byte IGNORE_BIT{0x80};
|
|
|
|
private:
|
|
std::optional<FSChaCha20> m_send_l_cipher;
|
|
std::optional<FSChaCha20> m_recv_l_cipher;
|
|
std::optional<FSChaCha20Poly1305> m_send_p_cipher;
|
|
std::optional<FSChaCha20Poly1305> m_recv_p_cipher;
|
|
|
|
CKey m_key;
|
|
EllSwiftPubKey m_our_pubkey;
|
|
|
|
std::array<std::byte, SESSION_ID_LEN> m_session_id;
|
|
std::array<std::byte, GARBAGE_TERMINATOR_LEN> m_send_garbage_terminator;
|
|
std::array<std::byte, GARBAGE_TERMINATOR_LEN> m_recv_garbage_terminator;
|
|
|
|
public:
|
|
/** No default constructor; keys must be provided to create a BIP324Cipher. */
|
|
BIP324Cipher() = delete;
|
|
|
|
/** Initialize a BIP324 cipher with specified key and encoding entropy (testing only). */
|
|
BIP324Cipher(const CKey& key, Span<const std::byte> ent32) noexcept;
|
|
|
|
/** Initialize a BIP324 cipher with specified key (testing only). */
|
|
BIP324Cipher(const CKey& key, const EllSwiftPubKey& pubkey) noexcept;
|
|
|
|
/** Retrieve our public key. */
|
|
const EllSwiftPubKey& GetOurPubKey() const noexcept { return m_our_pubkey; }
|
|
|
|
/** Initialize when the other side's public key is received. Can only be called once.
|
|
*
|
|
* initiator is set to true if we are the initiator establishing the v2 P2P connection.
|
|
* self_decrypt is only for testing, and swaps encryption/decryption keys, so that encryption
|
|
* and decryption can be tested without knowing the other side's private key.
|
|
*/
|
|
void Initialize(const EllSwiftPubKey& their_pubkey, bool initiator, bool self_decrypt = false) noexcept;
|
|
|
|
/** Determine whether this cipher is fully initialized. */
|
|
explicit operator bool() const noexcept { return m_send_l_cipher.has_value(); }
|
|
|
|
/** Encrypt a packet. Only after Initialize().
|
|
*
|
|
* It must hold that output.size() == contents.size() + EXPANSION.
|
|
*/
|
|
void Encrypt(Span<const std::byte> contents, Span<const std::byte> aad, bool ignore, Span<std::byte> output) noexcept;
|
|
|
|
/** Decrypt the length of a packet. Only after Initialize().
|
|
*
|
|
* It must hold that input.size() == LENGTH_LEN.
|
|
*/
|
|
unsigned DecryptLength(Span<const std::byte> input) noexcept;
|
|
|
|
/** Decrypt a packet. Only after Initialize().
|
|
*
|
|
* It must hold that input.size() + LENGTH_LEN == contents.size() + EXPANSION.
|
|
* Contents.size() must equal the length returned by DecryptLength.
|
|
*/
|
|
bool Decrypt(Span<const std::byte> input, Span<const std::byte> aad, bool& ignore, Span<std::byte> contents) noexcept;
|
|
|
|
/** Get the Session ID. Only after Initialize(). */
|
|
Span<const std::byte> GetSessionID() const noexcept { return m_session_id; }
|
|
|
|
/** Get the Garbage Terminator to send. Only after Initialize(). */
|
|
Span<const std::byte> GetSendGarbageTerminator() const noexcept { return m_send_garbage_terminator; }
|
|
|
|
/** Get the expected Garbage Terminator to receive. Only after Initialize(). */
|
|
Span<const std::byte> GetReceiveGarbageTerminator() const noexcept { return m_recv_garbage_terminator; }
|
|
};
|
|
|
|
#endif // BITCOIN_BIP324_H
|