Panama (cryptography)

Panama (cipher)

General
Designers	Joan Daemen, Craig Clapp
First published	December 1998
Derived from	StepRightUp
Successors	MUGI, RadioGatún, SHA-3
Cipher detail
Key sizes	256 bits

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 and SHA-3.

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.

Hash function

Panama (hash)

Cipher detail
Digest sizes	256 bits
Security claims	2128 (collision resistance)
Block sizes	256 bits
State size	8736 bits
Best public cryptanalysis
Panama hash collisions can be generated in 26 time.

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, at NIST's 2006 Second Cryptographic Hash Workshop, unveiled a Panama variant called RadioGatún. The hash function workings of RadioGatún does not have the known weaknesses that Panama's hash function has. In turn, RadioGatún inspired the new cryptographic standard SHA-3.

External links

• John Savard's page on Panama