The RIPEMD-160 Hash Algorithm
The RIPEMD-160 hashing algorithm is part of a family of algorithms developed in 1996. The original RIPEMD algorithm (created in 1992) was based off of the popular hashing algorithm of the time—MD4. It was designed to be a more secure version of MD4, suitable for projects that required higher levels of security.
After a number of security weaknesses were discovered with the original algorithm (most notably a hash collision), a small group of programmers created strenghtened versions of the original algorithm. RIPEMD-160 was one of them, and remains the most widely used.
Like other hashing algorithms, RIPEMD-160 takes an arbitrary input of bytes and produces a 20 byte (160 bit) output. It can be used to store passwords, credit cards, and other sensitive information. However, RIPEMD-160 is much slower than both MD5 and the SHA-2 family of algorithms. Notably, Bitcoin used RIPEMD-160 hashes for their older addresses as RIPEMD-160 is one of the shortest unique hash algorithms.