diff options
Diffstat (limited to 'src/key.h')
| -rw-r--r-- | src/key.h | 27 |
1 files changed, 27 insertions, 0 deletions
@@ -22,6 +22,12 @@ */ typedef std::vector<unsigned char, secure_allocator<unsigned char> > CPrivKey; +/** Size of ECDH shared secrets. */ +constexpr static size_t ECDH_SECRET_SIZE = CSHA256::OUTPUT_SIZE; + +// Used to represent ECDH shared secret (ECDH_SECRET_SIZE bytes) +using ECDHSecret = std::array<std::byte, ECDH_SECRET_SIZE>; + /** An encapsulated private key. */ class CKey { @@ -156,6 +162,27 @@ public: //! Load private key and check that public key matches. bool Load(const CPrivKey& privkey, const CPubKey& vchPubKey, bool fSkipCheck); + + /** Create an ellswift-encoded public key for this key, with specified entropy. + * + * entropy must be a 32-byte span with additional entropy to use in the encoding. Every + * public key has ~2^256 different encodings, and this function will deterministically pick + * one of them, based on entropy. Note that even without truly random entropy, the + * resulting encoding will be indistinguishable from uniform to any adversary who does not + * know the private key (because the private key itself is always used as entropy as well). + */ + EllSwiftPubKey EllSwiftCreate(Span<const std::byte> entropy) const; + + /** Compute a BIP324-style ECDH shared secret. + * + * - their_ellswift: EllSwiftPubKey that was received from the other side. + * - our_ellswift: EllSwiftPubKey that was sent to the other side (must have been generated + * from *this using EllSwiftCreate()). + * - initiating: whether we are the initiating party (true) or responding party (false). + */ + ECDHSecret ComputeBIP324ECDHSecret(const EllSwiftPubKey& their_ellswift, + const EllSwiftPubKey& our_ellswift, + bool initiating) const; }; struct CExtKey { |