Patent ID: 8060743

Claim:
A computer implemented method of operating a cryptographic unit for processing data to provide data confidentiality, data authenticity, or a combination thereof, said method comprising: said cryptographic unit determining a particular protection level, said particular protection level uniquely encoding therein a value M indicating length of an authentication tag to be associated with said data, and said particular protection level comprising an indication that selectively and individually invokes a setting for data confidentiality and data authenticity; said cryptographic unit constructing a nonce using said particular protection level, said nonce uniquely encoding said value M; said cryptographic unit accessing a first data element m and a second data element a; said cryptographic unit accessing said nonce, a key, and said value M; said cryptographic unit encrypting said first data element m and, if said indication indicates data authenticity, deriving an encrypted authentication tag based on said first data element m, said second data element a, said nonce, said key, and said value M; and said cryptographic unit outputting encrypted data c.