Why does crypt(3) use DES? `man 3 crypt` clearly states that it uses DES. I thought DES was deprecated, but I see no notice that crypt would be deprecated. **Why does it not use AES instead, and is`crypt(3)` deprecated?** Is it simply a case of "DES is secure enough for the purpose of this library", and that programs should use other libraries for encryption of important stuff?

`crypt` is easily breakable (it was in fact written by Robert Morris, a famous contributor to the early Unix, as a workbench for codebreaking activities) and should not be used for anything important.

From the `crypt` manpage:

> The DES algorithm itself has a few quirks which make the use of the crypt() interface a very poor choice for anything other than password authentication. If you are planning on using the crypt() interface for a cryptography project, don't do it: get a good book on encryption and one of the widely available DES libraries.

For any real-world use, there are cryptographically stronger alternatives available, such as `mcrypt` and `ccrypt` (which uses AES).