Cryptographic techniques play a major role in digital information security. In cryptography, securing/storing the cryptographic key is an arduous task. The proposed stable cryptographic key generation directly from fingerprint biometrics overcomes this security concern. It eradicates the need of storing a cryptographic key. Rather, the key can be generated from a fingerprint biometrics on a need basis. In this work, a novel Gray code-based method is introduced to generate a stable cryptographic key from fingerprint. Usage of Gray code representation significantly reduces the number of mismatch bits between the generated bit strings from the two instances of the same fingerprint. Hence, Reed-Solomon error correction code is able to successfully correct the errors which may occur due to variations in captured images of the same fingerprint. This generated bit string is used in a symmetric key setup for secure data storage.