BitShifting with BigIntegers in Java
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Published on 2010-04-28T05:20:15Z
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I am implementing DES Encryption in Java with use of BigIntegers.
I am left shifting binary keys with Java BigIntegers by doing the BigInteger.leftShift(int n) method. Key of N (Kn) is dependent on the result of the shift of Kn-1. The problem I am getting is that I am printing out the results after each key is generated and the shifting is not the expected out put. The key is split in 2 Cn and Dn (left and right respectively).
I am specifically attempting this: "To do a left shift, move each bit one place to the left, except for the first bit, which is cycled to the end of the block. "
It seems to tack on O's on the end depending on the shift. Not sure how to go about correcting this.
Results:
c0: 11110101010100110011000011110
d0: 11110001111001100110101010100
c1: 111101010101001100110000111100
d1: 111100011110011001101010101000
c2: 11110101010100110011000011110000
d2: 11110001111001100110101010100000
c3: 1111010101010011001100001111000000
d3: 1111000111100110011010101010000000
c4: 111101010101001100110000111100000000
d4: 111100011110011001101010101000000000
c5: 11110101010100110011000011110000000000
d5: 11110001111001100110101010100000000000
c6: 1111010101010011001100001111000000000000
d6: 1111000111100110011010101010000000000000
c7: 111101010101001100110000111100000000000000
d7: 111100011110011001101010101000000000000000
c8: 1111010101010011001100001111000000000000000
d8: 1111000111100110011010101010000000000000000
c9: 111101010101001100110000111100000000000000000
d9: 111100011110011001101010101000000000000000000
c10: 11110101010100110011000011110000000000000000000
d10: 11110001111001100110101010100000000000000000000
c11: 1111010101010011001100001111000000000000000000000
d11: 1111000111100110011010101010000000000000000000000
c12: 111101010101001100110000111100000000000000000000000
d12: 111100011110011001101010101000000000000000000000000
c13: 11110101010100110011000011110000000000000000000000000
d13: 11110001111001100110101010100000000000000000000000000
c14: 1111010101010011001100001111000000000000000000000000000
d14: 1111000111100110011010101010000000000000000000000000000
c15: 11110101010100110011000011110000000000000000000000000000
d15: 11110001111001100110101010100000000000000000000000000000
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