```{index} single: sha1_transform (Digest::SHA1) ``` ```{index} single: Digest::SHA1::sha1_transform ``` # sha1_transform The SHA-1 compression function over one 64-byte block, from the standard initial state: the 20-byte result, with no padding and no length. A block shorter than 64 bytes is padded with zero bytes; bytes past the 64th are not used. This is the function G of FIPS 186-2's random-number generator, not a digest of the data. ## Synopsis ```perl use Digest::SHA1 qw(sha1_transform); my $g = sha1_transform($xkey); ```