Chosen-prefix collisions for MD5 and applications

M.M.J. Stevens, A.K. Lenstra, B.M.M. Weger, de

Research output: Contribution to journalArticleAcademicpeer-review

26 Citations (Scopus)


We present a novel, automated way to find differential paths for MD5. Its main application is in the construction of chosen-prefix collisions. We have shown how, at an approximate expected cost of 239 calls to the MD5 compression function, for any two chosen message prefixes P and P', suffixes S and S' can be constructed such that the concatenated values P||S and P'||S' collide under MD5. The practical attack potential of this construction of chosen-prefix collisions is of greater concern than the MD5-collisions that were published before. This is illustrated by a pair of MD5-based X.509 certificates one of which was signed by a commercial Certification Authority (CA) as a legitimate website certificate, while the other one is a certificate for a rogue CA that is entirely under our control (cf. Other examples, such as MD5-colliding executables, are presented as well. More details can be found on
Original languageEnglish
Pages (from-to)322-359
JournalInternational Journal of Applied Cryptography
Issue number4
Publication statusPublished - 2012


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