Algorithm to create an encrypted Oracle password

Hello there,

do you know an algorithm for me, which is able to encrypt passwords,
which are compatible Oracle passwords? There is a maximum length
limitation in Oracle (30 chars) and the algorithm should not produce
an encrypted password longer than 30 characters, if the clear text
password is less than or equals 30 characters. The best algorithm for
me would be one, which always creates an encrypted password with a
length of 30 characters.

I need the algorithm for a C# (.NET) application.

Thank you,
Norbert