60 lines
1.2 KiB
Go
60 lines
1.2 KiB
Go
package crypto
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import (
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"crypto/rand"
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"encoding/binary"
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"git.gammaspectra.live/P2Pool/edwards25519"
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"git.gammaspectra.live/P2Pool/p2pool-observer/types"
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"unsafe"
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)
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func RandomScalar() *edwards25519.Scalar {
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buf := make([]byte, 32)
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for {
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if _, err := rand.Read(buf); err != nil {
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return nil
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}
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if !less32(buf, limit) {
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continue
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}
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scalar := BytesToScalar(buf)
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if scalar.Equal(zeroScalar) == 0 {
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return scalar
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}
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}
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}
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// DeterministicScalar consensus way of generating a deterministic scalar from given entropy
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// Slice entropy will have data appended
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func DeterministicScalar(entropy []byte) *edwards25519.Scalar {
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var counter uint32
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entropy = append(entropy, make([]byte, int(unsafe.Sizeof(counter)))...)
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n := len(entropy) - int(unsafe.Sizeof(counter))
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h := GetKeccak256Hasher()
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defer PutKeccak256Hasher(h)
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var hash types.Hash
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scalar := GetEdwards25519Scalar()
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for {
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h.Reset()
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counter++
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binary.LittleEndian.PutUint32(entropy[n:], counter)
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_, _ = h.Write(entropy)
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HashFastSum(h, hash[:])
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if !less32(hash[:], limit) {
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continue
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}
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scReduce32(hash[:])
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scalar, _ = scalar.SetCanonicalBytes(hash[:])
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if scalar.Equal(zeroScalar) == 0 {
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return scalar
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}
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}
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}
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