Birthday attacks are a class of brute-force techniques used in an attempt to solve a class of cryptographic hash function problems. These methods take advantage of functions which, when supplied with a random input, return one of equally likely values. By repeatedly evaluating the function for different inputs, the same output is expected to be obtained after about evaluations.

**References**

RSA Laboratories. ``Question 95. What is a Birthday Attack'' and ``Question 96. How Does the Length of a Hash Value Affect Security?''
http://www.rsa.com/rsalabs/faq/.
van Oorschot, P. and Wiener, M. ``A Known Plaintext Attack on Two-Key Triple Encryption.'' In
*Advances in Cryptology--Eurocrypt '90.* New York: Springer-Verlag, pp. 366-377, 1991.

Yuval, G. ``How to Swindle Rabin.'' *Cryptologia* **3**, 187-189, Jul. 1979.

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1999-05-26