KCV Calculator
Compute Key Check Values for 3DES and AES keys by encrypting zero data. Essential for key loading ceremonies and HSM validation.
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 KCV works
A Key Check Value is a short fingerprint of a cryptographic key used to verify that two parties share the same key without revealing the key itself.
3DES KCV: Encrypt 8 zero bytes (0000000000000000) with 3DES-ECB. Take the first 3 bytes. Double-length keys use EDE mode with K1 = K3.
AES KCV: Encrypt 16 zero bytes with AES-ECB (emulated via AES-CBC with zero IV — produces identical output for a single all-zero block). Take the first 3 bytes.