Create SHA256 hash in Clarity

Generate SHA-256 hashes from buffer data in Clarity smart contracts

(define-read-only (create-sha256-hash (data (buff 4096)))

  (sha256 (unwrap-panic (to-consensus-buff? data)))

)



;; Example usage

(define-read-only (hash-message (message (string-utf8 200)))

  (create-sha256-hash (unwrap-panic (to-consensus-buff? message)))

)



;; Hash a simple string

(print (hash-message u"Hello World"))

Use cases

  • Creating unique identifiers from data
  • Verifying data integrity in contracts
  • Implementing commit-reveal schemes
  • Building merkle trees for proofs

Key concepts

The SHA-256 implementation in Clarity:

  • Takes a buffer as input (max 1MB)
  • Returns a 32-byte buffer hash
  • Uses to-consensus-buff? to ensure consistent encoding
  • Produces the same hash as off-chain implementations

Contents

Use casesKey concepts