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Questions tagged [lfsr]

From Wikipedia: "In computing, a linear-feedback shift register (LFSR) is a shift register whose input bit is a linear function of its previous state."

For more information see: https://en.wikipedia.org/wiki/Linear-feedback_shift_register

43 questions
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VHDL-Implement LFSR

I write below Vhdl code & testbench code for implement LFSR on ISE. I pick up LFSR code from this path on ISE. Language Templates--VHDL--Synthesis Constructs--Coding Examples--- Counters---LFSR My problem is in simulink(isim), i always face with 'U'…
Sokhan Negar
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Verilog: assign a weighted sum of parameterized length

I am trying to implement a linear feedback shift register with parameterized width and coefficients: // ... parameter width = 16; parameter [width-1:0] coeff = 16'b1110101100110110; // ... Is there a way to assign the XOR-chain to the input…
Jersey
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Why does the sum of two adjacent sections of bitstream in an LFSR generate the same taps as the individual sections?

I have the sum (bitwise XOR) of 2 adjacent sections of bitstream in a 61 bit LFSR, I know what the taps should be for each individual section. When I feed this combined bitstream into a Berlekamp-Massey tool, it gives the same taps as the taps for…
Layan Jethwa
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Efficient Calculation of Linear Feedback Shift Register Iterations

I was wondering if it is feasible to determine the number of iterations required for the Linear Feedback Shift Register algorithm to generate the sequence let's say"1010" from the initial seed "1001," without the need to iterate through all possible…
Router
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Reverse engineering checksum calculation for Proflame 2 RF remote

Intro The SIT Proflame family of fireplace controllers is used in many brands of fireplaces. It uses an RF remote that transmits on 315MHz. I would like to be able to generate valid command packets for arbitrary serial numbers to control my…
Felix
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Is it possible to reverse the sequence of an LFSR if the GF(2) tap polynomial has the x^0 term set to zero?

While exploring how to generate maximum period forward and reverse sequences using an LFSR, I ran into some confusion regarding the definition of a GF(2) primitive polynomial. When I chose a primitive GF(2) polynomial from this table, all…
cookiecipher
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Re-roll next value in pseudo-random sequence without changing any other values

I would like a pseudo-random number generator which generates an effectively-infinite (i.e. very large period) sequence that can be traversed in both directions but also allows re-rolling the value under the cursor. For example, a starting view of…
Hello
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generator based on the LFSR

Implement a pseudo-random number generator based on the LFSR method. The polynomial should be provided by the user as a parameter. The program should generate bits "indefinitely" until the user stops the algorithm. Web app in C# aspx.cs: protected…
c.user
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Converting an integer to a bytes object in Python 3 results in a "Q" in PyCharm Debugger?

I am writing a function to implement a LFSR in Python 3. I've figured out the hard part, which is actually stepping through the state using the feedback value to get the key and getting all of the output bytes by ANDing the key and the input data.…
brainyclown10
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Linear-feedback shift register implementation

I want to implement a Linear-feedback shift register for the following polynomial x^24 + x^23 + x^22 + x^20 + x^19 + x^18 + x^17 + x^16 + x^15 + x^13 + x^12 + x^8 + x^7 + x^6 + 1, relying on what can be found here with the associated C…
Rico1990
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Linear-feedback shift register's taps in c++

I have a bit more specific question than before (maybe in old thread someone give more general answer) about using the "tap" on Linear-feedback shift in c++. I have scramler state of x7+x6+x2, so i need to XOR bytes number 7, 6, and 2, and then add…
Stiven
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Question about how to code the LFSR correctly

I found an example below of a linear feedback shift register program on Wikipedia but I didn't understand it at all : #include #include unsigned lfsr_fib() { uint16_t start_state = 0xACE1u; /* Any nonzero start state will…
Nobody
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Why LFSR stream code is not suitable for encryption?

Why LFSR stream code is not suitable for encryption? Is there a special attack for LFSR?
Mahdi
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trying to make an lfsr in js

i'm trying to make an lfsr in js, on its head every thing is looking good, i'm using strings and im converting them back and forth to get the last bit, my problem is printing the number i'm trying to make a large hex number, my logic is give me a…
Gidon Avziz
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32-Bit LFSR Encryption on a String in C++

I am trying to implement a LFSR to encrypt a string, but the catch is is that only on the 8th step of the LFSR is when the lowest byte is collected. My current code encrypts correctly (I believe), but not in the format I would like. I have to use…
Cameron Calderon
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