mirror of
https://github.com/RfidResearchGroup/proxmark3.git
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79 lines
1.9 KiB
Python
79 lines
1.9 KiB
Python
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# This code is contributed by
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# Shubham Singh(SHUBHAMSINGH10)
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# 2020, modified (@iceman1001)
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import sys
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# Python3 program to illustrate Compute the
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# parity of a number using XOR
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# Generating the look-up table while pre-processing
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def P2(n, table):
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table.extend([n, n ^ 1, n ^ 1, n])
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def P4(n, table):
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return (P2(n, table), P2(n ^ 1, table),
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P2(n ^ 1, table), P2(n, table))
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def P6(n, table):
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return (P4(n, table), P4(n ^ 1, table),
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P4(n ^ 1, table), P4(n, table))
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def LOOK_UP(table):
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return (P6(0, table), P6(1, table),
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P6(1, table), P6(0, table))
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# LOOK_UP is the macro expansion to generate the table
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table = [0] * 256
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LOOK_UP(table)
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# Function to find the parity
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def Parity(num) :
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# Number is considered to be of 32 bits
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max = 16
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# Dividing the number o 8-bit
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# chunks while performing X-OR
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while (max >= 8):
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num = num ^ (num >> max)
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max = max // 2
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# Masking the number with 0xff (11111111)
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# to produce valid 8-bit result
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return table[num & 0xff]
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def main():
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if(len(sys.argv) < 2):
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print("""
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\t{0} - Calculate parity of a given number
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Usage: {0} <2,10,16> <number>
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\t Specify type as in 2 Bin, 10 Decimal, 16 Hex, and number in that particular format
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\t number can only be 32bit long.
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Example:
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\t{0} 10 1234
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Should produce the output:
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\tOdd parity\n""".format(sys.argv[0]))
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return 0
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numtype= int(sys.argv[1], 10)
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print("numtype: {0}".format(numtype))
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input= int(sys.argv[2], numtype)
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print("num: {0} 0x{0:X}".format(input))
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#num = "001111100010100011101010111101011110"
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# Result is 1 for odd parity
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# 0 for even parity
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# result = Parity( int(input, numtype) )
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result = Parity(input)
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print("Odd parity") if result else print("Even parity")
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if __name__ == "__main__":
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main()
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