Created
February 20, 2010 15:24
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Efficient SQAM(Square-And-Multiply) method for very! large integers. Several hundred digits is fine.
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| def sqam(self, base, exponent, modulus): | |
| base = int(base) | |
| exponent = int(exponent) | |
| modulus = int(modulus) | |
| z = 1 | |
| expBin = bin(exponent)[2:] | |
| for i in expBin: | |
| if (i == "1"): | |
| z = base*z*z%modulus | |
| else: | |
| z = z*z%modulus | |
| return z |
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