# A structural analysis of the A5/1 state transition graph

@inproceedings{Beckmann2012ASA, title={A structural analysis of the A5/1 state transition graph}, author={Andreas Beckmann and Jaroslaw Fedorowicz and J{\"o}rg Keller and Ulrich Meyer}, booktitle={Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia}, year={2012} }

We describe efficient algorithms to analyze the cycle structure of the graph induced by the state transition function of the A5/1 stream cipher used in GSM mobile phones and report on the results of the implementation. [] Key Method This step does not break the overall structure of the graph and keeps at least one node on every cycle. In the third step the nodes of the reduced graph are connected by weighted edges.

## 12 Citations

### A Bitslice Implementation of Anderson’s Attack on A5/1

- Computer Science
- 2018

Using commonly available GPUs this method can quite efficiently recover the secret key using only 64 bits of keystream, and can be made even more efficient by harnessing the computing power of modern Graphics Processing Units (GPUs).

### Ant Colony-Inspired Parallel Algorithm to Improve Cryptographic Pseudo Random Number Generators

- Computer Science2017 IEEE Security and Privacy Workshops (SPW)
- 2017

A parallel algorithm to compute promising candidate states for modifying the state space of a pseudo-random number generator in order to increase its cycle length is presented, demonstrating high parallel efficiency that makes the algorithm well-suited even for massively parallel systems like GPUs.

### State Transition Analysis of GSM Encryption Algorithm A5/1

- Computer ScienceJournal of Communications Software and Systems
- 2022

The implementation of cryptanalytic on A5/1 techniques such as minimized state recovery for recovering the session key and the number of state transitions/updations needed for a state S to reoccur is maintained in the lookup table.

### Tweaking cryptographic primitives with moderate state space by direct manipulation

- Computer Science, Mathematics2017 IEEE International Conference on Communications (ICC)
- 2017

This work presents a greedy algorithm that searches those states of a chaotic PRNG and hash chains based on MD5 and SHA-3 with promising results and gives an implementation that only marginally increases the effort per state transition.

### Structural improvements of chaotic PRNG implementations

- Computer Science2016 11th International Conference for Internet Technology and Secured Transactions (ICITST)
- 2016

This paper presents a simple way to improve the state space structure of chaotic PRNGs by using a different parametrization of the chaotic function at certain iterations and hereby breaking out of these cycles.

### Analysis of PRNGs with Large State Spaces and Structural Improvements

- Computer Science
- 2014

This paper demonstrates that valuable additional information about the properties of the algorithm can be gathered by analyzing the state space, and two approaches are presented to make this analysis manageable.

### Proposed Enhancement of A5/1 stream cipher

- Computer Science, Mathematics2019 2nd International Conference on Engineering Technology and its Applications (IICETA)
- 2019

An enhancement of A5/1 is add fourth register to increase the total security of proposed algorithm and apply a new filtration functions on each register to strengthen the linear combination function (XOR) with remain same.

### 2 Metrics for a “ good ” PRNG

- Computer Science
- 2017

This paper presents a simple way to improve the state space structure of chaotic PRNGs by using a different parametrization of the chaotic function at certain iterations and hereby breaking out of these cycles.

### Security aspects of PRNGs with large state spaces

- Computer Science2015 10th International Conference for Internet Technology and Secured Transactions (ICITST)
- 2015

This paper demonstrates that valuable additional information about the properties of the algorithm can be gathered by analyzing the state space, and two approaches are presented to make this analysis manageable.

### Parallel Exploration of an Unknown Random Forest

- Computer Science
- 2018

We investigate how to explore with a parallel machine a random and unknown forest, of which we only know an upper bound on the total size, some leaves to start from, and the roots. The size of the…

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