Post-quantum algorithms use parameter-set-specific raw sizes. An ML-DSA-65 signature is 3,309 bytes, an ML-DSA-87 signature is 4,627 bytes, and SLH-DSA signatures range from 7,856 to 49,856 bytes. tryb decodes pasted hex or base64 locally and compares its exact byte length with the complete FIPS tables.
Length narrows possibilities; it does not identify or validate cryptography. Some sizes collide: ML-KEM-1024 uses 1,568 bytes for both its encapsulation key and ciphertext, all ML-KEM shared secrets are 32 bytes, and SLH-DSA key sizes overlap ordinary random or classical artifacts. Results therefore list every candidate instead of manufacturing certainty.
The tool also recognizes client and server key_exchange lengths from the active TLS ECDHE-MLKEM Internet-Draft, including X25519MLKEM768. Those are wire-context candidates with defined component order—not a claim that any arbitrary same-length concatenation is a hybrid key share.
Edge cases worth knowing
- Kyber versus ML-KEM
- Pre-standard Kyber and standardized ML-KEM are not interchangeable. Size cannot select the correct decoder; protocol labels and version context must do that.
- Raw versus wrapped keys
- PEM, ASN.1, PKCS #8, certificates, and protocol frames add metadata bytes. This matcher accepts raw hex or base64 only and compares the decoded raw length.
- Short colliding sizes
- A 32-, 48-, 64-, 96-, or 128-byte blob has many possible meanings. The PQC card remains a low-confidence secondary interpretation for these values.
Common mistakes
- Calling a same-length blob a valid post-quantum key or signature without parsing and validating its encoding.
- Assuming Kyber competition artifacts and standardized ML-KEM artifacts can be exchanged because their lengths match.
- Adding component lengths and declaring a generic hybrid construction without protocol-defined order and framing.
- Comparing a wrapped key or certificate length with a standard's raw artifact table.