‘sha1sum’ and ‘sha2’ utilities : Print or check SHA-1 digests SHA-2 digests
‘sha1sum’ computes a 160-bit checksum for each specified FILE. The usage and options of this command are precisely the same as for ‘md5sum’.
Note: The SHA-1 digest is more secure than MD5, and no collisions of it are known (different files having the same fingerprint). However, it is known that they can be produced with considerable, but not unreasonable, resources. For this reason, it is generally considered that SHA-1 should be gradually phased out in favor of the more secure SHA-2 hash algorithms.
The commands ‘sha224sum’, ‘sha256sum’, ‘sha384sum’ and ‘sha512sum’ compute checksums of various lengths (respectively 224, 256, 384 and 512 bits), collectively known as the SHA-2 hashes. The usage and options of these commands are precisely the same as for ‘md5sum’.
Note: The SHA384 and SHA512 digests are considerably slower to compute, especially on 32-bit computers, than SHA224 or SHA256.