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hash: Use size_t instead of int for RFC6979 outlen copy #1729

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Merged
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Sep 2, 2025
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hash: Use size_t instead of int for RFC6979 outlen copy #1729

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2 changes: 1 addition & 1 deletion src/hash_impl.h
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@real-or-random real-or-random Sep 1, 2025 •
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If you want to improve this further, I'd suggest

  • renaming now to chunk_len (consistency with the SHA256 implementation above)
  • moving the entire if block just below the initialization of now (or chunk_len). (The goal is to compute max(outlen, 32). Spreading this over two blocks is a bit silly. It's probably a result of the C89 rule that declarations need to be at the beginning of a block. edit: Indeed, see 792bcdb#diff-e91b67aa33d606267c28ce5da48a89cc789f4081c176eb581a9bff780afd1d6cR260-L262 )

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Thanks! I'll hold off for the moment. Hopefully it'll inspire someone to replace this nonce generation process with something more lightweight and straightforward like BIP340's approach. :)

Original file line number Diff line number Diff line change
Expand Up @@ -265,7 +265,7 @@ static void secp256k1_rfc6979_hmac_sha256_generate(secp256k1_rfc6979_hmac_sha256

while (outlen > 0) {
secp256k1_hmac_sha256 hmac;
int now = outlen;
size_t now = outlen;
secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
secp256k1_hmac_sha256_finalize(&hmac, rng->v);
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