discover encryption method

[richard () tortoise demon co uk]

Hi All,

An application I use stores user passwords in a database table, but in
some encrypted form. I know all the passwords both in plain text and
in their encrypted form. Is there any tool I could use that can take
two such lists and tell me what encryption method is being used?

The application itself can display user passwords, so I assume the
encryption method must be symmetric.

Thanks for any help,

Richard