29 lines
627 B
Go
29 lines
627 B
Go
package paillier
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import (
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"crypto/rand"
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"io"
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"math/big"
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)
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var ZERO = big.NewInt(0)
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var ONE = big.NewInt(1)
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var TWO = big.NewInt(2)
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var FOUR = big.NewInt(4)
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// Generate a random element in the group of all the elements in Z/nZ that
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// has a multiplicative inverse.
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func GetRandomNumberInMultiplicativeGroup(n *big.Int, random io.Reader) (*big.Int, error) {
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r, err := rand.Int(random, n)
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if err != nil {
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return nil, err
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}
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zero := big.NewInt(0)
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one := big.NewInt(1)
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if zero.Cmp(r) == 0 || one.Cmp(new(big.Int).GCD(nil, nil, n, r)) != 0 {
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return GetRandomNumberInMultiplicativeGroup(n, random)
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}
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return r, nil
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}
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