mirror of
https://source.quilibrium.com/quilibrium/ceremonyclient.git
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43 lines
799 B
Go
43 lines
799 B
Go
//
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// Copyright Coinbase, Inc. All Rights Reserved.
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//
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// SPDX-License-Identifier: Apache-2.0
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//
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package core
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import (
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"crypto/rand"
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"fmt"
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"math"
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"math/big"
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)
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// GenerateSafePrime creates a prime number `p`
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// where (`p`-1)/2 is also prime with at least `bits`
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func GenerateSafePrime(bits uint) (*big.Int, error) {
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if bits < 3 {
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return nil, fmt.Errorf("safe prime size must be at least 3-bits")
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}
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var p *big.Int
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var err error
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checks := int(math.Max(float64(bits)/16, 8))
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for {
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// rand.Prime throws an error if bits < 2
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// -1 so the Sophie-Germain prime is 1023 bits
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// and the Safe prime is 1024
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p, err = rand.Prime(rand.Reader, int(bits)-1)
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if err != nil {
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return nil, err
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}
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p.Add(p.Lsh(p, 1), One)
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if p.ProbablyPrime(checks) {
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break
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}
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}
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return p, nil
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}
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