Cryptographic key management apparatus and methods

The present invention provides for a cryptographic key management method and apparatus in which the cryptographic keys are provided as vector keys in that they comprise a key value and control information for specifying the use to which the key can be put by members of a communications domain. Each domain member is associated with at least one pair of vector keys and the keys in each pair share the same key value. One of the keys in each pair is provided as a public key and specified for encrypting, or verifying the seal of, messages sent from the domain member associated therewith and the other is provided as a private key and specified for decrypting, or generating a seal for, messages sent to the domain member associated therewith.