CalculateHashConstant
Calculate the constant for the secondary / supplemental hash function, so
that the hash function mixes the input bits as much as possible.
| Methods |
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| static long |
calcMultiplicativeInverse(long a)
Calculate the multiplicative inverse of a value (int).
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| static long |
calcMultiplicativeInverse(long a)
Calculate the multiplicative inverse of a value (int).
Parameters:
a - the value
Returns:
the multiplicative inverse
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| static long |
calcMultiplicativeInverseLong(long a)
Calculate the multiplicative inverse of a value (long).
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| static long |
calcMultiplicativeInverseLong(long a)
Calculate the multiplicative inverse of a value (long).
Parameters:
a - the value
Returns:
the multiplicative inverse
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| static void |
main(String... args)
Run just this test.
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| static void |
main(String... args) throws Exception
Run just this test.
Parameters:
args - ignored
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| int |
getAvalanche(CalculateHashConstant h, int value)
Calculate the number of bits that change if a single bit is changed
multiplied by 1000 (expected: 16000 +/- 5%).
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| int |
getAvalanche(CalculateHashConstant h, int value)
Calculate the number of bits that change if a single bit is changed
multiplied by 1000 (expected: 16000 +/- 5%).
Parameters:
h - the hash object
value - the base value
Returns:
the number of bit changes multiplied by 1000
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| long |
getCollisionCount()
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| long |
getCollisionCount()
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| int[] |
getDependencies(CalculateHashConstant h, int[] values)
Calculate how much the bit changes (output bits that change if an input
bit is changed) are independent of each other.
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| int[] |
getDependencies(CalculateHashConstant h, int[] values)
Calculate how much the bit changes (output bits that change if an input
bit is changed) are independent of each other.
Parameters:
h - the hash object
values - the values to test with
Returns:
the minimum and maximum number of output bits that are changed in
combination with another output bit
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| int[] |
getEffect(CalculateHashConstant h, int count, int seed)
Calculate if the all bit changes (that an output bit changes if an input
bit is changed) are within a certain range.
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| int[] |
getEffect(CalculateHashConstant h, int count, int seed)
Calculate if the all bit changes (that an output bit changes if an input
bit is changed) are within a certain range.
Parameters:
h - the hash object
count - the number of values to test
seed - the random seed
Returns:
the minimum and maximum value of all input-to-output bit changes
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| long |
getEffectSquare(CalculateHashConstant h, int[] values)
Calculate the sum of the square of the distance to the expected
probability that an output bit changes if an input bit is changed.
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| long |
getEffectSquare(CalculateHashConstant h, int[] values)
Calculate the sum of the square of the distance to the expected
probability that an output bit changes if an input bit is changed. The
lower the value, the better.
Parameters:
h - the hash object
values - the values to test with
Returns:
sum(distance^2)
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| int |
hash(int x)
The hash method.
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| int |
hash(int x)
The hash method.
Parameters:
x - the input
Returns:
the output
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| void |
run()
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| void |
run()
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| int |
secureHash(int x)
Calculate a hash using AES.
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| int |
secureHash(int x)
Calculate a hash using AES.
Parameters:
x - the input
Returns:
the output
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| void |
storeRandomFile()
Store a random file to be analyzed by the Diehard test.
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| void |
storeRandomFile() throws Exception
Store a random file to be analyzed by the Diehard test.
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