crypt

Applies a one-way cryptographic hash to str by invoking the standard library function crypt(3) with the given salt string. While the format and the result are system and implementation dependent, using a salt matching the regular expression \A[a-zA-Z0-9./]{2} should be valid and safe on any platform, in which only the first two characters are significant.

This method is for use in system specific scripts, so if you want a cross-platform hash function consider using Digest or OpenSSL instead.