Message-Digest algorithm
lastmod 2025-01-15created 2015-03-126 edits
MD4
The MD4 Message-Digest Algorithm is a cryptographic hash function developed by Ronald Rivest in 1990. The digest length is 128 bits. The algorithm has influenced later designs, such as the MD5, SHA-1 and RIPEMD algorithms.
MD5
MD5 (Message-Digest algorithm 5) is a 128-bit cryptographic hash function. It is specified as RFC 1321 and is mainly used for integrity checks, such as verifying that a program or file is unchanged from the original. It was devised by Ronald Rivest in 1991 to replace the earlier MD4.
In 1996, a design flaw was found in MD5. This was not a very serious flaw, but cryptographers began recommending other secure algorithms such as SHA-1 for hashing. In 2004, more serious cryptographic flaws were found, and in 2006 an algorithm was published that was fast enough to find a hash collision within a minute using the computing power of a single laptop. Today, using the MD5 algorithm for security-related purposes is not recommended, as it can cause serious security problems. In December 2008, it was announced that the flaws in MD5 could be used to forge SSL certificates.
MD5 concepts
MD5 is a kind of hash function that evolved through MD2, MD4, and MD5. What are MD2, MD4, and MD5? MD2, MD4, and MD5 are message-digest algorithms developed by Rivest.
They are intended for digital signature applications, where a large message has to be "compressed" in a secure manner before being signed with the private key. All three algorithms take a message of arbitrary length and produce a 128-bit message digest. While the structures of these algorithms are somewhat similar, the design of MD2 is quite different from that of MD4 and MD5; MD2 was optimized for 8-bit machines, whereas Md4 and Md5 were aimed at 32-bit machines.
The source code and descriptions of these three algorithms can be found in Internet RFCs 1319-1321. MD2 was developed by Rivest in 1989. The message is first padded so that its length is divisible by 16 bytes. A 16-byte checksum is then appended to the message, and the hash value is computed on the resulting message. Rogier and Chauvaud found that collisions for MD2 could be constructed if the calculation of the checksum were omitted. This is the only known attack result for MD2. MD4 was developed by Rivest in 1990. The message is padded to ensure that its length plus 448 bits is divisible by 512 bits. A 64-bit binary representation of the original length of the message is then concatenated to the message. The message is processed in 512-bit blocks in the Damgard/Markle iterative structure, and each block is processed in three distinct rounds. Attacks on versions of Md4 with either the first or the last rounds omitted were developed quickly by Den Boer and Bosselaers and others. Dobbertin showed how collisions for the full version of MD4 could be found in minutes on a PC. Clearly, MD4 can be considered broken.
MD5 was developed by Rivest in 1991. It is based on MD4 with "safety belts," and although it is slightly slower than MD4, it is more secure. The algorithm consists of four distinct rounds, designed slightly differently from MD4. The message-digest size, as well as the padding requirements, remain the same. Den Boer and Bosselaers found pseudo-collisions for MD5, but there are no other known attack results. Van Oorschot and Wiener considered a brute-force attack to find collisions in hash functions, and they estimated that a collision search machine designed specifically for MD5 could find a collision for MD5 in 24 days on average. The general technique can be applied to other hash functions.
JavaScript hashing speed comparison MD5 vs SHA-256
- MD5 is slower than SHA-256 and less secure.
- MD5 is a hash algorithm used in the past and is no longer cryptographically secure.
- SHA-256 provides a 256-bit hash output and offers higher security.
- In the tests, SHA-256 also outperformed MD5 in processing speed.
- The tests were run with modern JavaScript runtimes.
- Tests were run on ARM and Intel systems using Bun 1.31 and Node.js 23.
- Performance was compared on Apple M2, Intel Ice Lake, and Amazon Graviton 4 systems.
- SHA-256 performs faster on modern processors.
- On the Apple M2 system, MD5 recorded a throughput of 0.7 GB/s and SHA-256 2.6 GB/s.
- SHA-256 also outperformed MD5 on Intel and ARM-based systems.
- Modern processors provide cryptographic extensions to accelerate SHA-256.
- It is recommended not to use MD5 in practice.
- It is safer to use SHA-256 as a strong alternative to replace MD5, which has security problems.
- SHA-256 provides both security and performance, ensuring encryption and data integrity.