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| author | Pieter Wuille <pieter@wuille.net> | 2020-09-11 14:32:50 -0700 |
|---|---|---|
| committer | Pieter Wuille <pieter@wuille.net> | 2020-10-12 02:06:32 -0700 |
| commit | 9eb590894f15ff40806039bfd32972fbc260e30d (patch) | |
| tree | 74ddd22d2750eb0de88176a108aa9a7ecc57fe6f | |
| parent | 450d2b23710ad296eede81339195376021ab5500 (diff) | |
Add TaggedHash function (BIP 340)
This adds the TaggedHash function as defined by BIP340 to the hash module, which
is used in BIP340 and BIP341 to produce domain-separated hashes.
| -rw-r--r-- | src/hash.cpp | 10 | ||||
| -rw-r--r-- | src/hash.h | 9 |
2 files changed, 19 insertions, 0 deletions
diff --git a/src/hash.cpp b/src/hash.cpp index 83b90ae063..3657b38639 100644 --- a/src/hash.cpp +++ b/src/hash.cpp @@ -6,6 +6,7 @@ #include <crypto/common.h> #include <crypto/hmac_sha512.h> +#include <string> inline uint32_t ROTL32(uint32_t x, int8_t r) { @@ -84,3 +85,12 @@ uint256 SHA256Uint256(const uint256& input) CSHA256().Write(input.begin(), 32).Finalize(result.begin()); return result; } + +CHashWriter TaggedHash(const std::string& tag) +{ + CHashWriter writer(SER_GETHASH, 0); + uint256 taghash; + CSHA256().Write((const unsigned char*)tag.data(), tag.size()).Finalize(taghash.begin()); + writer << taghash << taghash; + return writer; +} diff --git a/src/hash.h b/src/hash.h index c16bbb48ce..6d876076ee 100644 --- a/src/hash.h +++ b/src/hash.h @@ -15,6 +15,7 @@ #include <uint256.h> #include <version.h> +#include <string> #include <vector> typedef uint256 ChainCode; @@ -202,4 +203,12 @@ unsigned int MurmurHash3(unsigned int nHashSeed, Span<const unsigned char> vData void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64]); +/** Return a CHashWriter primed for tagged hashes (as specified in BIP 340). + * + * The returned object will have SHA256(tag) written to it twice (= 64 bytes). + * A tagged hash can be computed by feeding the message into this object, and + * then calling CHashWriter::GetSHA256(). + */ +CHashWriter TaggedHash(const std::string& tag); + #endif // BITCOIN_HASH_H |