Generating Number and putting in Byte Array

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The idea is to generate non cryptographic numbers using a Linear Congruential Generator. It has an internal state consisting of a number xi initially set to x0 = seed. I need to take out the output bytes of given length from this generator.

print("The formula is: X(k+1) = a * Xk + c mod m")
seed_num = int(input("Enter seed number: "))
multiplier = int(input("Enter the multiplier(a): "))
increment = int(input("Enter the increment(c): "))
modulus = int(input("Enter the modulus (m): "))
unit = int(input("How many random numbers would you like to generate?\nInput: "))


def lcg():
    num_base = seed_num
    for i in range(unit, 0, -1):
        rd = (multiplier * num_base + increment) % modulus
        print(rd)
        num_base = rd


lcg()

I need to get a byte array from what is being generated using this LCG code. I need the output bytes sequentially starting from the byte generated in the first iteration and ending with the byte generated in the last iteration.

cryptography python
2 Answers

I think you are looking for bytearray() function.

lcg = [16, 25, 37, 53, 1, 5, 47, 48, 31, 45, 27, 3, 26, 20, 12, 38, 36, 15, 42, 23, 16, 25, 37, 53, 1, 5, 47, 48, 31, 45, 27, 3, 26, 20, 12, 38, 36, 15, 42, 23, 16, 25, 37, 53, 1, 5, 47, 48, 31, 45, 27, 3, 26, 20, 12, 38, 36, 15]
bytearray(lcg) # bytearray(b'\x10\x19%5\x01\x05/0\x1f-\x1b\x03\x1a\x14\x0c&$\x0f*\x17\x10\x19%5\x01\x05/0\x1f-\x1b\x03\x1a\x14\x0c&$\x0f*\x17\x10\x19%5\x01\x05/0\x1f-\x1b\x03\x1a\x14\x0c&$\x0f')

If you want to just convert a number to byte, you can also do this:

bytes([x])

where x is an integer from 0 to 255.

If this is not what you are looking for, please add an example of what you want to do.

JimChr - R4GN4R0

As the bytes are created in the lcg() function they can be added to a bytearray variable and returned at the end of the function. For example:

print("The formula is: X(k+1) = a * Xk + c mod m")
seed_num = 9999  # int(input("Enter seed number: "))
multiplier = 14  # int(input("Enter the multiplier(a): "))
increment = 12  # int(input("Enter the increment(c): "))
modulus = 128  # int(input("Enter the modulus (m): "))
unit = 4  # int(input("How many random numbers would you like to generate?\nInput: "))


def lcg():
    result = bytearray()
    num_base = seed_num
    for i in range(unit, 0, -1):
        rd = (multiplier * num_base + increment) % modulus
        print(rd)
        num_base = rd
        result.append(rd)
    return result


lcg_result = lcg()
print(f"raw bytearray: {lcg_result}")
print(f"As list: {list(lcg_result)}")
print(f"As hex value: {lcg_result.hex()}")

Which gave the following output:

The formula is: X(k+1) = a * Xk + c mod m
94
48
44
116
raw bytearray: bytearray(b'^0,t')
As list: [94, 48, 44, 116]
As hex value: 5e302c74
ukBaz0
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