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Trail of Bits released SequenceHash and SequenceMAC, open-source, hash-agnostic constructions for securely processing multiple distinct values without ambiguity. The designs length-encode inputs and use a double-hash construction to prevent input-boundary confusion and mitigate length-extension attacks when an underlying hash is susceptible. SequenceMAC provides keyed authentication, requires keys of at least 32 bytes, and includes key metadata intended to prevent HMAC-style key pseudocollisions.
The specification has been published through the Community Cryptography Specification Project (C2SP), alongside Rust, Go, and Python implementations and test vectors. Trail of Bits said the constructions can support domain separation, commitments, and Fiat-Shamir-style protocols, but cautioned implementers to use secure underlying hashes and consistent protocol encodings. The release addresses use cases similar to NIST SP 800-185's TupleHash, which defines unambiguous hashing for tuples of strings among SHA-3-derived cryptographic functions.
See the reporting duties and controls this puts on the clock.
3 events from the most recent confirmed update back to the earliest known activity.
NIST published Special Publication 800-185, defining the SHA-3-derived cSHAKE, KMAC, TupleHash, and ParallelHash functions.
Trail of Bits introduced hash-agnostic SequenceHash and keyed SequenceMAC constructions, publishing their specification through C2SP along with Rust, Go, and Python implementations and test vectors.
A NIST planning note states that NIST decided to revise Special Publication 800-185.
See what this changes for your reporting obligations and which controls it puts on the clock.
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blog.trailofbits.com
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