I've done a few of these conversions, and they are unpretty, to say the least. Part of it is that, as others have noted, we don't know the encryption/decryption is. Also, you hint that there has been a partial decryption; that might make certain canned solutions invalid, since they might do something you don't wish to have done again.

Also, I've seen that some mainframes don't always use the same values to mean the same characters. That is frightening. I ran across this when one of our customers was having trouble translating a file. Apparently, their computer was using "incomplete UTF-EBCDIC", which as you might guess wasn't precisely the same as the EBCDIC others were using.

Just FYI.

--
tbone1, YAPS (Yet Another Perl Schlub)
And remember, if he succeeds, so what.
- Chick McGee