Deleted file decryption software?!

Hi all, was hoping you could help me pls. My hubby put some sort of program on our computer that decrypted old emails, messenger conversations and pages viewed etc. - even ones that had been deleted. (he was snooping lol ) ...... He's now deleted the program but I'm interested in getting some of that stuff back!
Does anyone know what this program is and where I can get it as a free download?
Thanks in advance!
Apple

 

if you have stuff that was encrypted,and now you want to decrypt it, you must have the program that originally encrypted it and the key.
If you don't know what program you used to encrypt the data, your out of luck-you'll most likely never get the data back.

 

Ty MellowMan - I didn't actually encrypt it.....its was mainly yahoo emails and messages that he read (so he said lol) and I wanted to know how he brought them up since they arent even in my archive anymore.
Is there such a program? or has he put a keylogger or something on a while ago and is fibbing about how he snooped lol