You won't believe this....
I made a document in Acrobat 9 on my Win7 computer, password protected it, typed it in a 2nd time, then saved the document. Just seconds later, I went to test the document to make sure it'd open, so I tried to open it, and ..... it wouldn't open. It said 'wrong password'. So I must have had my fingers on the keyboard in the wrong home base position, and typed something other than I thought. I typed the same "password" with my fingers in different spots on the keyboard, but couldn't replicate the mistake.
How can I retrieve a password?
1) I thought there was something on computers where you could find out previous keystrokes, especially if you've not yet turned off your computer. I read one time where you do some steps then paste the results onto a .txt file, and it will show your previous keystrokes.
2) I almost bought one of those Password Recovery software programs online last night from Daosoft. I wonder if they're a scam, or if they really work?
You can't recover the password. If you could, I could have as well and the whole purpose of encryption would be moot. This is why it is a good practice to save the original PDF before you secure it.
If the password that you created was a really strong one (other than word 'password' or some other word) I doubt that the password recovery programs would do the work. They are usually good only for fairly simple passwords.
Acrobat X added new way of encryption that is almost impossible to crack and Acrobat XI added the password strength indicator which tells you how good the password that you're entering is.