Hi John,

>.NET = "203A7BB0530C0347082039D9583A4CF7153695A35EA6C16D92013F5A45E" (59 chars)

That's a pretty strange length, since it involves half a byte being converted to hex. If you convert the rc4.CryptedText property into a byte array and write this to a file, is the result still different from VFP? It's impossible to tell what the code is doing from the brief snippet. However, when the values are actually String, keep in mind that C# uses unicode strings. The string might have been converted to UTF-8 before it's been converted to hex. Encryption routines should always operate on byte arrays and streams, not on strings.