| // 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 hybrid |
| |
| // KEMKey represents a KEM managed key. |
| type KEMKey struct { |
| Kem, SymmetricKey []byte |
| } |
| |
| // ECIESHKDFSenderKem represents HKDF-based ECIES-KEM (key encapsulation mechanism) |
| //for ECIES sender. |
| type ECIESHKDFSenderKem struct { |
| recipientPublicKey *ECPublicKey |
| } |
| |
| // GenerateKey a HDKF based KEM. |
| func (s *ECIESHKDFSenderKem) encapsulate(hashAlg string, salt []byte, info []byte, keySize uint32, pointFormat string) (*KEMKey, error) { |
| |
| pvt, err := GenerateECDHKeyPair(s.recipientPublicKey.Curve) |
| if err != nil { |
| return nil, err |
| } |
| pub := pvt.PublicKey |
| secret, err := ComputeSharedSecret(&s.recipientPublicKey.Point, pvt) |
| if err != nil { |
| return nil, err |
| } |
| |
| sdata, err := pointEncode(pub.Curve, pointFormat, pub.Point) |
| if err != nil { |
| return nil, err |
| } |
| i := append(sdata, secret...) |
| |
| sKey, err := computeHKDF(hashAlg, i, salt, info, keySize) |
| if err != nil { |
| return nil, err |
| } |
| |
| return &KEMKey{ |
| Kem: sdata, |
| SymmetricKey: sKey, |
| }, nil |
| |
| } |