github.com/mysteriumnetwork/node@v0.0.0-20240516044423-365054f76801/services/wireguard/key/key.go (about)

     1  /*
     2   * Copyright (C) 2018 The "MysteriumNetwork/node" Authors.
     3   *
     4   * This program is free software: you can redistribute it and/or modify
     5   * it under the terms of the GNU General Public License as published by
     6   * the Free Software Foundation, either version 3 of the License, or
     7   * (at your option) any later version.
     8   *
     9   * This program is distributed in the hope that it will be useful,
    10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    12   * GNU General Public License for more details.
    13   *
    14   * You should have received a copy of the GNU General Public License
    15   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    16   */
    17  
    18  package key
    19  
    20  import (
    21  	"crypto/rand"
    22  	"encoding/base64"
    23  
    24  	"github.com/pkg/errors"
    25  	"golang.org/x/crypto/curve25519"
    26  )
    27  
    28  const keyLength = 32
    29  
    30  // PrivateKeyToPublicKey generates wireguard public key from private key
    31  func PrivateKeyToPublicKey(key string) (string, error) {
    32  	k, err := base64.StdEncoding.DecodeString(key)
    33  	if err != nil {
    34  		return "", err
    35  	}
    36  
    37  	var pub [keyLength]byte
    38  	var priv [keyLength]byte
    39  	copy(priv[:], k[:keyLength])
    40  	curve25519.ScalarBaseMult(&pub, &priv)
    41  
    42  	return base64.StdEncoding.EncodeToString(pub[:]), nil
    43  }
    44  
    45  // GeneratePrivateKey generates a private key
    46  func GeneratePrivateKey() (string, error) {
    47  	randomBytes := make([]byte, keyLength)
    48  	if _, err := rand.Read(randomBytes); err != nil {
    49  		return "", errors.Wrapf(err, "failed to generate random bytes for private key")
    50  	}
    51  
    52  	// https://cr.yp.to/ecdh.html
    53  	randomBytes[0] &= 248
    54  	randomBytes[31] &= 127
    55  	randomBytes[31] |= 64
    56  
    57  	return base64.StdEncoding.EncodeToString(randomBytes), nil
    58  }