A system and method are described supporting secure implementations of 3DES and other strong cryptographic algorithms. A secure key block having control, key, and hash fields safely stores or transmits keys in insecure or hostile environments. The control field provides attribute information such as the manner of using a key, the algorithm to be implemented, the mode of use, and the exportability of the key. A hash algorithm is applied across the key and control for generating a hash field that cryptographically ties the control and key fields together. Improved security is provided because tampering with any portion of the key block results in an invalid key block. The work factor associated with any manner of attack is sufficient to maintain a high level of security consistent with the large keys and strong cryptographic algorithms supported.