SEm/escapeLab/LFSR
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− | The aim of this task is to find the proper feedback function of an LFSR | + | The aim of this task is to find the proper feedback function of an LFSR within a remote control emitter. |
This value is the second key to opening the safe. | This value is the second key to opening the safe. | ||
= Specifications = | = Specifications = | ||
− | 4-bit Galois LFSR | + | |
+ | A system comprising an RF emitter and a receiver allows to transmit a button press. | ||
+ | When the emitter is powered via USB, it continuously sends the output bit of a 4-bit Galois LFSR. | ||
+ | The receiver is connected to an FPGA board and a LED is switched on when the proper code is received. | ||
+ | |||
+ | The position of the LFSR XOR feed-in taps has to be found in order to match to the receiver. | ||
+ | These positions correspond to the '1's of a 4-bit binary number, which is the value to find. |
Revision as of 13:40, 24 April 2018
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Welcome to the SEM escape lab
Finding the feedback terms of an LFSR
The aim of this task is to find the proper feedback function of an LFSR within a remote control emitter. This value is the second key to opening the safe.
Specifications
A system comprising an RF emitter and a receiver allows to transmit a button press. When the emitter is powered via USB, it continuously sends the output bit of a 4-bit Galois LFSR. The receiver is connected to an FPGA board and a LED is switched on when the proper code is received.
The position of the LFSR XOR feed-in taps has to be found in order to match to the receiver. These positions correspond to the '1's of a 4-bit binary number, which is the value to find.