HSM Key Composer
XOR clear key components into a TDES or AES key, check each component’s KCV and DES parity, and get the combined key’s KCV — for key loading ceremonies.
Follows ANSI X9.24-12017·verified Oct 2026· double-checked Oct 2026— XOR components; TDES KCV = encrypt zeros (3 bytes); AES KCV = AES-CMAC of zeros (5 bytes) plus legacy AES-ECB; DES odd parity; RFC 4493 CMAC vectors
Use test data only. All calculations run locally in your browser — PayProbe never sees, transmits, or stores your PAN, CVV, keys, PINs, or cryptographic inputs. How we handle data →
How it works
Each custodian holds one full-length component; the key is the XOR of all of them, so every component is needed (n-of-n — this is not an m-of-n threshold scheme). PCI PIN requires at least two components, each held by a different custodian, and each custodian checks their component’s KCV when entering it.
TDES KCV: encrypt 8 zero bytes with the key (EDE, K3 = K1 for a double-length key); leftmost 3 bytes.
AES KCV: ANSI X9.24-1:2017 and TR-31:2018 (KCV algorithm 01) use AES-CMAC of 16 zero bytes, leftmost 5 bytes. The legacy method (TR-31 algorithm 00) encrypts 16 zero bytes with AES-ECB; it is shown too, as 3 bytes, because many HSMs and older procedures still print it — check which one your HSM reports.