| In cryptography, a Key Checksum Value (KCV) is the checksum of a cryptographic key. It is used to validate the key integrity or compare keys without knowing their actual values. The KCV is computed by encrypting a block of bytes, each with value '00' or '01', with the cryptographic key and retaining the first 6 hexadecimal characters of the encrypted result. It is used in key management in different ciphering devices, like SIM-cards or Hardware Security Modules (HSM).
In the GlobalPlatform technical specifications the KCV is defined for DES/3DES and AES keys as follows:
For a DES key, the key check value is computed by encrypting 8 bytes, each with value '00', with the key to be checked and retaining the 3 highest-order bytes of the encrypted result. For a AES key, the key check value is computed by encrypting 16 bytes, each with value '01', with the key to be checked and retaining the 3 highest-order bytes of the encrypted result.
The same definition is used by the GSMA. |
