Use the similar encryption procedure to decrypt the password.
Procedure
Place the encrypted string in the command prompt instead of the text password. For example, $MQ_HOME/bin>passwordEncryptDecryptTool.bat "cfMrxokzKTm3zJJLpDW7Jg==".
After entering the encrypted string as input, the utility returns the original decrypted password. In this case, tibco123.
Warning: You must specify double quotes for the text password or encrypted password, else the utility does not perform encryption or decryption.