The U.S. government published the Data Encryption Standard in 1977 as a proposed standard cryptosystem for all government communications. However, it is **no longer considered as secure**. It is now superseded by the [[Advanced Encryption Standard]] (AES). DES is a 64-bit block cipher that has five modes of operation: - Electronic Codebook (ECB) - Cipher Block Chaining (CBC) - Cipher Feedback (CFB) - Output Feedback (OFB) - Counter (CTR) All of the DES modes operate on 64 bits of plaintext at a time to generate 64-bit blocks of cipher text. The *key used by DES is 56 bits* long. An adapted version of DES, **Triple DES** (3DES), uses the same algorithm three times with three different encryption keys to produce a more secure encryption. However, even the 3DES algorithm is now considered insecure, and it is deprecated as of December 2023.