Key Block Decoder
Decode an ANSI X9.143 (TR-31) or Thales payShield key block into its header fields and optional blocks. Supply the key block protection key (KBPK) to verify the MAC and recover the wrapped key. Build a block the other direction too.
Everything runs in your browser — no key material is sent anywhere. Even so, prefer test keys: a web page is not the place for production key material.
Paste a key block to detect its dialect
Key material never leaves your browser.
Thales blocks are protected by keys already derived from the LMK, not the LMK itself — that derivation is proprietary to the HSM and cannot be reproduced here. Supply the encryption and authentication keys directly.
Optional blocks
Key material never leaves your browser.