Get password from a known key-iv-combination (RijndaelManaged in C#)

Is it possible to "calculate" a valid password string when the Key开发者_运维问答 and the IV (as strings) for a RijndaelManaged-Key are known?

No it should not be possible. It depends which key derivation function you use, but usually password and salt are repeatably hashed with MD5 or SHA1 so virtually impossible.