TEA results_eac3

Brief introduction

TEA (Tiny Encryption Algorithm) is used by other research labs for testing, how their EA distinguisher works.

TEA is block cipher, it uses 128 bit key, works with 64 bits blocks and for encryption, Feistel network of 64 rounds = 32 cycles is used (64 rounds of Feistel network is not corresponding to our term "round". Other teams also uses term round for one cycle).

Results of other teams

Other teams used traditional method of EA. They evolve bit masks, whose are ANDed od ORed with output of TEA. This result is measured -- from simple measurement of weight, to some statistical methods.

J. C. Hernández, J. M. Sierra, P. Isasi, A. Ribagorda, Genetic Cryptoanalysis of Two Rounds TEA [2002]

2 rounds solved.

J. C. Hernandez and P. Isasi, Finding Efficient Distinguishers for Cryptographic Mappings, with an Application to the Block Cipher TEA [27 JUL 2004]

proved TEA is weak with 4 rounds.

Cryptanalysis of TEA Using Quantum-Inspired Genetic Algorithms [OCT 2009]

4-5 rounds broken.

Other teams with lower results with later date are skipped.

Our measured data

Used settings

statistical evaluator 26
30k generations
populations size 1 (replacement size 1)
until now we used only gate circuits, polynomials are next target
TEA is limited in range 1 -- 32 rounds (32 rounds is full TEA)
plaintext type is 3, because TEA is now implemented in ECB mode, so we input biased (95%) data to circuit. Random data as input means, that cipher have to insert some pattern into the data, which is not probable. We have to try input sequence of increasing counter and also random input is tried. But results without comment on plaintext uses plaintext type 3.
key type is 2
TODO: think about other possible settings