Panama (cryptography)

Panama

General
Designers	Joan Daemen, Craig Clapp
First published	February 2002
Derived from	StepRightUp
Successors	MUGI
Cipher detail
Key sizes	256 bits
Best public cryptanalysis
Panama hash collisions can be generated in 26 time.

Panama is a cryptography primitive which can be used both as a hash function and a stream cipher. Based on StepRightUp, it was designed by Joan Daemen and Craig Clapp and presented in the paper Fast Hashing and Stream Encryption with PANAMA on the Fast Software Encryption (FSE) conference 1998. The cipher has influenced several other designs, for example MUGI.

The primitive can be used both as a hash function and a stream cipher. The stream cipher uses a 256-bit key and the performance of the cipher is very good reaching 2 cycles per byte.

As a hash function, collisions have been shown by Vincent Rijmen et al. in the paper Producing Collisions for PANAMA presented at FSE 2001. The attack shows a computational complexity of 2⁸² and with negligible memory requirements.

At FSE 2007, Joan Daemen and Gilles Van Assche presented a practical attack on the Panama hash function that generates a collision in 2⁶ evaluations of the state updating function.

Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche proposed, at NIST's 2006 Second Cryptographic Hash Workshop, unveiled a Panama variant called RadioGatún. RadioGatún is strictly a hash function; it does not have the known weaknesses that Panama's hash function has.

External links

• John Savard's page on Panama
• J. Daemen, G. Van Assche "Producing Collisions for Panama Instantaneously"