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Rump session CRYPTO 2009
Hash Functions and Cayley Graphs:
the end of the story?
Christophe Petit
Jean-Jacques Quisquater
UCL Crypto Group
Rump session CRYPTO 2009
The dream
Rump session CRYPTO 2009
Recently
Rump session CRYPTO 2009
Hash functions (1990-...) designed by randomness?
Rump session CRYPTO 2009
Zemor-Tillich hash functions1994-2009
Rump session CRYPTO 2009
Rump session CRYPTO 2009
IACR eprint 2009-376
Rump session CRYPTO 2009
Rump session CRYPTO 2009
Rump session CRYPTO 2009
Rump session CRYPTO 2009
Conclusion I
Rump session CRYPTO 2009
Conclusion II
• Zemor-Tillich is completely broken• Preimage in few seconds with a
small program• Length of the preimage around
100.000 bits
Rump session CRYPTO 2009
End?
• No!• Changing the generators• More generators• Working in other algebra• A new field!