# Online KCV Calculator

The Key Checksum Value (KCV) is the checksum of a cryptographic key. It is used to validate the key integrity or match the 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).

The exact procedure to compute the KCV depends on the ciphering algorithm. According to the GlobalPlatform and the GSMA specifications, the KCV for a DES or 3DES key is computed by encrypting 8 bytes, each with value '00', while the KCV for an AES key is computed by encrypting 16 bytes, each with value '01'.

The KCV calculator assumes that the input key is either DES or 3DES.

Note that it is never recommended to input a real cryptographic key into an online tool. You can save this page and use it offline to make sure that sensitive information is not sent over the Internet.

A valid DES or 3DES key must be 8, 16 or 24 bytes long, which means that the key length in hexadecimal characters must be 16, 32 or 48. For example, a valid DES key: 0123456789ABCDEF