Ransomware is probably the most dangerous type of malware. When a computer is infected with ransomware, ransomware starts to encrypt targeted types of files (for example, JPG, DOC, XLS, MOV, AVI, VMDK, VHD, VDI) with a long encryption key. The encrypted files are corrupted files that cannot be repaired in most cases. After encrypting files, ransomware demands that a user pay money for decrypting files within a limited period of time. However, in most cases, retrieving files is impossible as they cannot be repaired/decrypted even after paying money. Finding the decryption key is almost impossible. For example, the time needed to crack a 128-bit key takes 500 billion years with the current performance level of computers. Thus, encrypted files are irreversibly corrupted files in this case.