JSON Canonicalization Scheme (JCS)

RFC 8785 defines a deterministic method for transforming JSON into a consistent byte stream for cryptographic hashing and digital signatures.

RFC 8785 eliminates the inherent variability of JSON serialization by enforcing a strict, deterministic format. It handles the three primary sources of inconsistency: property ordering (lexicographical sorting), number representation (using the Ryū algorithm for minimal decimal output), and whitespace (complete removal). This ensures that two distinct systems processing the same logical data produce an identical byte-for-byte output. It serves as a critical component for security frameworks like WebAuthn and various JSON Web Signature (JWS) implementations where hash consistency is non-negotiable.

https://datatracker.ietf.org/doc/html/rfc8785