The simplest mode encrypts and decrypts each 128-bit block separately. One key decrypts a plaintext, while the other encrypts it. It transparently encrypts files, using an arbitrary directory as storage for the encrypted files. File encryption encrypts a single file. File level encryption encrypts only the file contents. That makes the encryptor (receiver) unaware of whether it encrypts or decrypts the key. Disk encryption refers to encryption technology that encrypts data on a hard disk drive. GSM primarily encrypts communications content using the A5/1 call encryption cypher. Tresorit encrypts files using client-side encryption with AES-256 before uploading them. Each triple encryption encrypts one block of 64 bits of data. WinBIOS encrypts the stored password, using a simple substitution cipher. KeePass encrypts the database with the AES or Twofish symmetric ciphers. Unlike telnet, OpenSSH encrypts all information (including usernames and passwords). The password that encrypts a document also restricts the user from opening the document. It uses TCP (Transmission Control Protocol) for transport and encrypts the whole packet.