Calculates the sha1 hash of str
using the
US Secure Hash Algorithm 1,
and returns that hash. The hash is a 40-character hexadecimal number.
If the optional raw_output
is set to TRUE,
then the sha1 digest is instead returned in raw binary format with a
length of 20.
注意: The optional
raw_output
parameter was added in PHP 5.0.0 and defaults to FALSE
See also sha1_file(), crc32(), and md5()