Hello Russ, Thank you very much FIP 180-2 gives a clarification: "When a message of any length < 2^64 bits (for SHA-1 and SHA-256) or < 2^128 bits (for SHA-384 and SHA-512) is input to an algorithm, the result is an output called a message digest. -- Best regards, Maxim Masiutin Ritlabs SRL http://www.ritlabs.com/