52 lines
1.1 KiB
Go
52 lines
1.1 KiB
Go
package tool
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import (
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"crypto/rand"
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"encoding/base64"
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"github.com/pkg/errors"
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"golang.org/x/crypto/curve25519"
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)
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func Curve25519Genkey(StdEncoding bool, inputBase64 string) (public, private string, err error) {
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var privateKey, publicKey []byte
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var encoding *base64.Encoding
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if StdEncoding {
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encoding = base64.StdEncoding
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} else {
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encoding = base64.RawURLEncoding
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}
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if len(inputBase64) > 0 {
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privateKey, err = encoding.DecodeString(inputBase64)
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if err != nil {
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goto out
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}
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if len(privateKey) != curve25519.ScalarSize {
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err = errors.New("Invalid length of private key.")
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goto out
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}
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}
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if privateKey == nil {
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privateKey = make([]byte, curve25519.ScalarSize)
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if _, err = rand.Read(privateKey); err != nil {
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goto out
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}
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}
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// Modify random bytes using algorithm described at:
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// https://cr.yp.to/ecdh.html.
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privateKey[0] &= 248
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privateKey[31] &= 127 | 64
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if publicKey, err = curve25519.X25519(privateKey, curve25519.Basepoint); err != nil {
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goto out
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}
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public = encoding.EncodeToString(publicKey)
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private = encoding.EncodeToString(privateKey)
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out:
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return public, private, err
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}
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