The SHA2 instruction calculates a SHA2 hash value from a given data area. The length of the resulting hash value is defined by the HashLen parameter. The following values are supported: 224, 256, 384 and 512.
The calculation is made according to the FIPS PUB 180-4 "Secure Hash Standard (SHS)". The SHA-224 algorithm is used for the hash value 224, and the SHA-256 algorithm for the hash value 256.
The size of the data area is not limited, because only data segments with a maximum length of 8192 bytes are used internally by the CPU for calculation. If the data area is larger than 8192 bytes, it is divided by the CPU into smaller segments. The hash value is delivered only after the processing of SHA2 is completed.