This tool can decrypt files encrypted with Tesla/AlphaCrypt when you have the
key.dat file. The Key.dat file can be found on C:UsersusernameAppDataRoamingkey.dat of the infected computer.
1) Backup your encrypted files just in case things don't go right.
2) Download
TeslaDecoder.zip file and extract to a local folder.
2) Run the TeslaDecoder.exe
3) Click
Load data file and browse the location of your key.dat file and select
4) Click the
Decrypt Folder button and select your encrypted folder or folders

All your files should be decrypted and log file will be created on the same folder as the exe file.