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// Copyright 2020 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 hybrid_test
// [START hybrid-example]
import (
"bytes"
"fmt"
"log"
"github.com/tink-crypto/tink-go/v2/hybrid"
"github.com/tink-crypto/tink-go/v2/insecurecleartextkeyset"
"github.com/tink-crypto/tink-go/v2/keyset"
)
func Example() {
// A private keyset created with
// "tinkey create-keyset --key-template=DHKEM_X25519_HKDF_SHA256_HKDF_SHA256_AES_256_GCM --out private_keyset.cfg".
// Note that this keyset has the secret key information in cleartext.
privateJSONKeyset := `{
"key": [{
"keyData": {
"keyMaterialType":
"ASYMMETRIC_PRIVATE",
"typeUrl":
"type.googleapis.com/google.crypto.tink.HpkePrivateKey",
"value":
"EioSBggBEAEYAhogVWQpmQoz74jcAp5WOD36KiBQ71MVCpn2iWfOzWLtKV4aINfn8qlMbyijNJcCzrafjsgJ493ZZGN256KTfKw0WN+p"
},
"keyId": 958452012,
"outputPrefixType": "TINK",
"status": "ENABLED"
}],
"primaryKeyId": 958452012
}`
// The corresponding public keyset created with
// "tinkey create-public-keyset --in private_keyset.cfg".
publicJSONKeyset := `{
"key": [{
"keyData": {
"keyMaterialType":
"ASYMMETRIC_PUBLIC",
"typeUrl":
"type.googleapis.com/google.crypto.tink.HpkePublicKey",
"value":
"EgYIARABGAIaIFVkKZkKM++I3AKeVjg9+iogUO9TFQqZ9olnzs1i7Sle"
},
"keyId": 958452012,
"outputPrefixType": "TINK",
"status": "ENABLED"
}],
"primaryKeyId": 958452012
}`
// Create a keyset handle from the keyset containing the public key. Because the
// public keyset does not contain any secrets, we can use [keyset.ReadWithNoSecrets].
publicKeysetHandle, err := keyset.ReadWithNoSecrets(
keyset.NewJSONReader(bytes.NewBufferString(publicJSONKeyset)))
if err != nil {
log.Fatal(err)
}
// Retrieve the HybridEncrypt primitive from publicKeysetHandle.
encPrimitive, err := hybrid.NewHybridEncrypt(publicKeysetHandle)
if err != nil {
log.Fatal(err)
}
plaintext := []byte("message")
encryptionContext := []byte("encryption context")
ciphertext, err := encPrimitive.Encrypt(plaintext, encryptionContext)
if err != nil {
log.Fatal(err)
}
// Create a keyset handle from the cleartext private keyset in the previous
// step. The keyset handle provides abstract access to the underlying keyset to
// limit the access of the raw key material.
//
// WARNING: In practice, it is unlikely you will want to use a insecurecleartextkeyset,
// as it implies that your key material is passed in cleartext, which is a security risk.
// Consider encrypting it with a remote key in Cloud KMS, AWS KMS or HashiCorp Vault.
// See https://developers.google.com/tink/key-management-overview.
privateKeysetHandle, err := insecurecleartextkeyset.Read(
keyset.NewJSONReader(bytes.NewBufferString(privateJSONKeyset)))
if err != nil {
log.Fatal(err)
}
// Retrieve the HybridDecrypt primitive from privateKeysetHandle.
decPrimitive, err := hybrid.NewHybridDecrypt(privateKeysetHandle)
if err != nil {
log.Fatal(err)
}
decrypted, err := decPrimitive.Decrypt(ciphertext, encryptionContext)
if err != nil {
log.Fatal(err)
}
fmt.Println(string(decrypted))
// Output: message
}
// [END hybrid-example]
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