password encryption

[محروم.كوم]

I am writing some applications in C# that users log in. The plan was to have the users use th same log in credentials they use on my forums* and I wrote the query strings to test but so far I have been unable to output the same encrpted value.

I know that I can't view the passwords and don't care about this* I am just looking to match encrpted value for encripted value for account check.

I read some archived stuff though that vbulletin uses a non standard encription* so can anyone(preferably in C#) give an indication on how to match the encription? __DEFINE_LIKE_SHARE__