Message Digest 2

What Does Message Digest 2 Mean?

Message Digest 2 is a hash function used in cryptography. Developed in 1989 by Ronald Rivest, it is byte-oriented, producing a 128-bit hash value with the help of an arbitrary length message. It is optimized for 8-bit computers. Message Digest 2 was developed mainly to be used for digital signature applications, which required a secured and compressed large file to be signed with a private key. Although it remains in use in public key infrastructures, it is rarely used as it takes a long time to compute and is no longer considered secure.


Techopedia Explains Message Digest 2

Message Digest 2 depends on the random permutation of bytes. Thirty-two-digit hexadecimal numbers are used for representing the 128-bit Message Digest 2 hashes. The Message Digest 2 algorithm makes use of a message of any length and produces an output of a 128-bit message digest of the input. It is assumed that it is impossible to produce two messages with same message digest or to obtain a prespecified target message digest from a given message. The process of the Message Digest 2 algorithm involves the following steps: appending padding bytes, appending checksum, initializing the message digest buffer for computing the message digest, processing the message in 16-byte blocks and finally producing the output.

One of the biggest benefits of Message Digest 2 is its simplicity in implementation. However, Message Digest 2 is slower when compared to Message Digest 4 or 5. This is because it was optimized for 8-bit computers, whereas Message Digest 4 and 5 were optimized for 32-bit machines. Again, comparing secure hash algorithms such as SHA-1 or SHA-256, Message Digest 2 algorithms are slower in performance. However, it was discovered that message digest 2 could leak information of the keys with collision attacks, which is why it is no longer favored.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…