| // Copyright 2021 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| package subtle |
| |
| import ( |
| "crypto/rand" |
| |
| "golang.org/x/crypto/curve25519" |
| ) |
| |
| // GeneratePrivateKeyX25519 generates a new 32-byte private key. |
| func GeneratePrivateKeyX25519() ([]byte, error) { |
| privKey := make([]byte, curve25519.ScalarSize) |
| _, err := rand.Read(privKey) |
| return privKey, err |
| } |
| |
| // ComputeSharedSecretX25519 returns the 32-byte shared key, i.e. |
| // privKey * pubValue on the curve. |
| func ComputeSharedSecretX25519(privKey, pubValue []byte) ([]byte, error) { |
| return curve25519.X25519(privKey, pubValue) |
| } |
| |
| // PublicFromPrivateX25519 computes privKey's corresponding public key. |
| func PublicFromPrivateX25519(privKey []byte) ([]byte, error) { |
| return ComputeSharedSecretX25519(privKey, curve25519.Basepoint) |
| } |