Revocable key generation from irrevocable biometric data for symmetric cryptography Crypto-biometric system (CBS) is a combination of biometrie with cryptography to enhance network security. Biometrie is the most trustworthy measure to identify a person uniquely using his or her behavioral and physiological characteristics. Cryptography is an effective concern to the security of information. The security of cryptography depends on the strength of cryptographic key and strength of key depends on the length of key. In the traditional cryptography, key is generated randomly and it is very difficult to remember as the key is not linked with user. To address this limitation of cryptography, CBS uses biometrie data of user to bind key with its owner and as the key is linked with user’s biometrie data, user does not need to remember the key. As biometrie data is irrevocable, it becomes useless when compromised and as a result the biometrie based key becomes also useless. In this approach, fingerprint features are used to generate key for cryptographic application. The key is revocable and easy to revoke when required. In our experiment, FVC2004 fingerprint database is used to investigate the result.