The Data Encryption Standard (DES) was approved as Federal Information Processing Standard (FIPS) 46 on January 15, 1977 by the National Bureau of Standards (now NIST). The standard specified “an encryption algorithm which is to be implemented in an electronic device for use in Federal ADP systems and networks,” laying out the mathematical steps required to transform computer data into a cryptographic cipher and to reverse the process.
DES grew out of an IBM cipher design and was the first encryption algorithm endorsed by the U.S. government for protecting unclassified but sensitive data. Because it was a public, published standard, it could be implemented by anyone and was scrutinized openly, which helped make it the dominant symmetric cipher of its era in banking, networking, and commerce.
The algorithm is a block cipher: it operates on fixed 64-bit blocks of data under a key. Its central weakness was the small effective key length of 56 bits, which over time became vulnerable to exhaustive brute-force search as computing power grew cheaper. By the late 1990s, dedicated hardware could recover a DES key in days.
The original FIPS 46 was later superseded by revised editions and eventually withdrawn. Its limitations prompted NIST to run an open competition for a replacement, which produced the Advanced Encryption Standard (AES) in 2001.