Digest Access Authentication - Impact of MD5 Security On Digest Authentication

Impact of MD5 Security On Digest Authentication

The MD5 calculations used in HTTP digest authentication is intended to be "one way", meaning that it should be difficult to determine the original input when only the output is known. If the password itself is too simple, however, then it may be possible to test all possible inputs and find a matching output (a brute-force attack) – perhaps aided by a dictionary or suitable look-up list.

The HTTP scheme was designed by Phillip Hallam-Baker at CERN in 1993 and does not incorporate subsequent improvements in authentication systems, such as the development of keyed-hash message authentication code (HMAC). Although the cryptographic construction that is used is based on the MD5 hash function, collision attacks were in 2004 generally believed to not affect applications where the plaintext (i.e. password) is not known. However, claims in 2006 (Kim, Biryukov2, Preneel, Hong, "On the Security of HMAC and NMAC Based on HAVAL MD4 MD5 SHA-0 and SHA-1") cause some doubt over other MD5 applications as well. So far, however, MD5 collision attacks have not been shown to pose a threat to digest authentication, and the RFC 2617 allows servers to implement mechanisms to detect some collision and replay attacks.

Read more about this topic:  Digest Access Authentication

Famous quotes containing the words impact of, impact, security and/or digest:

    One can describe a landscape in many different words and sentences, but one would not normally cut up a picture of a landscape and rearrange it in different patterns in order to describe it in different ways. Because a photograph is not composed of discrete units strung out in a linear row of meaningful pieces, we do not understand it by looking at one element after another in a set sequence. The photograph is understood in one act of seeing; it is perceived in a gestalt.
    Joshua Meyrowitz, U.S. educator, media critic. “The Blurring of Public and Private Behaviors,” No Sense of Place: The Impact of Electronic Media on Social Behavior, Oxford University Press (1985)

    If the federal government had been around when the Creator was putting His hand to this state, Indiana wouldn’t be here. It’d still be waiting for an environmental impact statement.
    Ronald Reagan (b. 1911)

    It seems to me that our three basic needs, for food and security and love, are so mixed and mingled and entwined that we cannot straightly think of one without the others. So it happens that when I write of hunger, I am really writing about love and the hunger for it, and warmth and the love of it and the hunger for it ... and then the warmth and richness and fine reality of hunger satisfied ... and it is all one.
    M.F.K. Fisher (b. 1908)

    For I pray that God will digest me.
    Anne Sexton (1928–1974)