對於大多數公開金鑰加密用途，我們建議使用 DHKEM_X25519_HKDF_SHA256、HKDF_SHA256、AES_256_GCM 金鑰類型的基本加密混合型加密基本功能。
公開金鑰加密包含使用兩個金鑰保護資料：一個公開金鑰和一個私密金鑰。「公開金鑰」用於加密，並使用「私密金鑰」進行解密。如果傳送者無法儲存密鑰，且需要用公開金鑰加密資料，這會是理想的選擇。
下列範例可協助您開始使用混合型加密原始物件：
C++
// A command-line utility for testing Tink Hybrid Encryption.
#include <iostream>
#include <memory>
#include <ostream>
#include <string>
#include "absl/flags/flag.h"
#include "absl/flags/parse.h"
#include "absl/log/check.h"
#include "absl/strings/string_view.h"
#include "util/util.h"
#ifndef TINK_EXAMPLES_EXCLUDE_HPKE
#include "tink/hybrid/hpke_config.h"
#endif
#include "tink/hybrid/hybrid_config.h"
#include "tink/hybrid_decrypt.h"
#include "tink/hybrid_encrypt.h"
#include "tink/keyset_handle.h"
#include "tink/util/status.h"
ABSL_FLAG(std::string, keyset_filename, "", "Keyset file in JSON format");
ABSL_FLAG(std::string, mode, "", "Mode of operation {encrypt|decrypt}");
ABSL_FLAG(std::string, input_filename, "", "Input file name");
ABSL_FLAG(std::string, output_filename, "", "Output file name");
ABSL_FLAG(std::string, context_info, "",
"Context info for Hybrid Encryption/Decryption");
namespace {
using ::crypto::tink::HybridDecrypt;
using ::crypto::tink::HybridEncrypt;
using ::crypto::tink::KeysetHandle;
using ::crypto::tink::util::Status;
using ::crypto::tink::util::StatusOr;
constexpr absl::string_view kEncrypt = "encrypt";
constexpr absl::string_view kDecrypt = "decrypt";
void ValidateParams() {
// ...
}
} // namespace
namespace tink_cc_examples {
Status HybridCli(absl::string_view mode, const std::string& keyset_filename,
const std::string& input_filename,
const std::string& output_filename,
absl::string_view context_info) {
Status result = crypto::tink::HybridConfig::Register();
if (!result.ok()) return result;
#ifndef TINK_EXAMPLES_EXCLUDE_HPKE
// HPKE isn't supported when using OpenSSL as a backend.
result = crypto::tink::RegisterHpke();
if (!result.ok()) return result;
#endif
// Read the keyset from file.
StatusOr<std::unique_ptr<KeysetHandle>> keyset_handle =
ReadJsonCleartextKeyset(keyset_filename);
if (!keyset_handle.ok()) return keyset_handle.status();
// Read the input.
StatusOr<std::string> input_file_content = ReadFile(input_filename);
if (!input_file_content.ok()) return input_file_content.status();
// Compute the output.
std::string output;
if (mode == kEncrypt) {
// Get the hybrid encryption primitive.
StatusOr<std::unique_ptr<HybridEncrypt>> hybrid_encrypt_primitive =
(*keyset_handle)
->GetPrimitive<crypto::tink::HybridEncrypt>(
crypto::tink::ConfigGlobalRegistry());
if (!hybrid_encrypt_primitive.ok()) {
return hybrid_encrypt_primitive.status();
}
// Generate the ciphertext.
StatusOr<std::string> encrypt_result =
(*hybrid_encrypt_primitive)->Encrypt(*input_file_content, context_info);
if (!encrypt_result.ok()) return encrypt_result.status();
output = encrypt_result.value();
} else { // operation == kDecrypt.
// Get the hybrid decryption primitive.
StatusOr<std::unique_ptr<HybridDecrypt>> hybrid_decrypt_primitive =
(*keyset_handle)
->GetPrimitive<crypto::tink::HybridDecrypt>(
crypto::tink::ConfigGlobalRegistry());
if (!hybrid_decrypt_primitive.ok()) {
return hybrid_decrypt_primitive.status();
}
// Recover the plaintext.
StatusOr<std::string> decrypt_result =
(*hybrid_decrypt_primitive)->Decrypt(*input_file_content, context_info);
if (!decrypt_result.ok()) return decrypt_result.status();
output = decrypt_result.value();
}
// Write the output to the output file.
return WriteToFile(output, output_filename);
}
} // namespace tink_cc_examples
int main(int argc, char** argv) {
absl::ParseCommandLine(argc, argv);
ValidateParams();
std::string mode = absl::GetFlag(FLAGS_mode);
std::string keyset_filename = absl::GetFlag(FLAGS_keyset_filename);
std::string input_filename = absl::GetFlag(FLAGS_input_filename);
std::string output_filename = absl::GetFlag(FLAGS_output_filename);
std::string context_info = absl::GetFlag(FLAGS_context_info);
std::clog << "Using keyset from file " << keyset_filename << " to hybrid "
<< mode << " file " << input_filename << " with context info '"
<< context_info << "'." << std::endl;
std::clog << "The resulting output will be written to " << output_filename
<< std::endl;
CHECK_OK(tink_cc_examples::HybridCli(mode, keyset_filename, input_filename,
output_filename, context_info));
return 0;
}
查看
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://github.com/google/tink/blob/master/docs/GOLANG-HOWTO.md#storing-and-loading-existing-keysets.
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
}
Java
package hybrid;
import static java.nio.charset.StandardCharsets.UTF_8;
import com.google.crypto.tink.HybridDecrypt;
import com.google.crypto.tink.HybridEncrypt;
import com.google.crypto.tink.InsecureSecretKeyAccess;
import com.google.crypto.tink.KeysetHandle;
import com.google.crypto.tink.TinkJsonProtoKeysetFormat;
import com.google.crypto.tink.hybrid.HybridConfig;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
/**
* A command-line utility for hybrid encryption.
*
* <p>It loads cleartext keys from disk - this is not recommended!
*
* <p>It requires the following arguments:
*
* <ul>
* <li>mode: either 'encrypt' or 'decrypt'.
* <li>key-file: Read the key material from this file.
* <li>input-file: Read the input from this file.
* <li>output-file: Write the result to this file.
* <li>[optional] contex-info: Bind the encryption to this context info.
*/
public final class HybridExample {
public static void main(String[] args) throws Exception {
if (args.length != 4 && args.length != 5) {
System.err.printf("Expected 4 or 5 parameters, got %d\n", args.length);
System.err.println(
"Usage: java HybridExample encrypt/decrypt key-file input-file output-file context-info");
System.exit(1);
}
String mode = args[0];
if (!mode.equals("encrypt") && !mode.equals("decrypt")) {
System.err.println("Incorrect mode. Please select encrypt or decrypt.");
System.exit(1);
}
Path keyFile = Paths.get(args[1]);
Path inputFile = Paths.get(args[2]);
byte[] input = Files.readAllBytes(inputFile);
Path outputFile = Paths.get(args[3]);
byte[] contextInfo = new byte[0];
if (args.length == 5) {
contextInfo = args[4].getBytes(UTF_8);
}
// Register all hybrid encryption key types with the Tink runtime.
HybridConfig.register();
// Read the keyset into a KeysetHandle.
KeysetHandle handle =
TinkJsonProtoKeysetFormat.parseKeyset(
new String(Files.readAllBytes(keyFile), UTF_8), InsecureSecretKeyAccess.get());
if (mode.equals("encrypt")) {
// Get the primitive.
HybridEncrypt encryptor = handle.getPrimitive(HybridEncrypt.class);
// Use the primitive to encrypt data.
byte[] ciphertext = encryptor.encrypt(input, contextInfo);
Files.write(outputFile, ciphertext);
} else {
HybridDecrypt decryptor = handle.getPrimitive(HybridDecrypt.class);
// Use the primitive to decrypt data.
byte[] plaintext = decryptor.decrypt(input, contextInfo);
Files.write(outputFile, plaintext);
}
}
private HybridExample() {}
}
Obj-C
Python
import tink
from tink import hybrid
from tink import secret_key_access
def example():
"""Encrypt and decrypt using hybrid encryption."""
# Register the hybrid encryption key managers. This is needed to create
# HybridEncrypt and HybridDecrypt primitives later.
hybrid.register()
# 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.
private_keyset = r"""{
"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"
public_keyset = r"""{
"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
# this keyset does not contain any secrets, we can use
# `parse_without_secret`.
public_keyset_handle = tink.json_proto_keyset_format.parse_without_secret(
public_keyset
)
# Retrieve the HybridEncrypt primitive from the keyset handle.
enc_primitive = public_keyset_handle.primitive(hybrid.HybridEncrypt)
# Use enc_primitive to encrypt a message. In this case the primary key of the
# keyset will be used (which is also the only key in this example).
ciphertext = enc_primitive.encrypt(b'message', b'context_info')
# Create a keyset handle from the private keyset. The keyset handle provides
# abstract access to the underlying keyset to limit the exposure of accessing
# the raw key material. WARNING: In practice, it is unlikely you will want to
# use a tink.json_proto_keyset_format.parse, as it implies that your key
# material is passed in cleartext which is a security risk.
private_keyset_handle = tink.json_proto_keyset_format.parse(
private_keyset, secret_key_access.TOKEN
)
# Retrieve the HybridDecrypt primitive from the private keyset handle.
dec_primitive = private_keyset_handle.primitive(hybrid.HybridDecrypt)
# Use dec_primitive to decrypt the message. Decrypt finds the correct key in
# the keyset and decrypts the ciphertext. If no key is found or decryption
# fails, it raises an error.
decrypted = dec_primitive.decrypt(ciphertext, b'context_info')
混合型加密
混合型加密基本功能結合對稱加密的效率與公開金鑰 (非對稱式) 密碼編譯的便利性。任何人都可以使用公開金鑰加密資料，但只有知道私密金鑰的使用者才能解密資料。
針對混合型加密，傳送者會產生新的對稱金鑰，用於加密每則訊息的明文並產生密文。該對稱金鑰會與收件者的公開金鑰封裝。如果是混合解密，對稱金鑰會由接收者「淘汰」，然後用於解密密文來復原原始明文。如要進一步瞭解如何儲存或傳送密文以及金鑰封裝，請參閱 Tink 混合型加密傳輸格式。
混合型加密具有下列屬性：
- 密碼：除非有人能存取私密金鑰，否則無法取得已加密明文的任何相關資訊 (長度除外)。
- 非對稱式：您可以使用公開金鑰加密密文，但如要解密，則必須使用私密金鑰。
- 隨機：系統以隨機方式加密。具有相同明文的兩個訊息不會產生相同密文。這可以防止攻擊者知道哪個密文對應至指定明文。
Tink 採用的混合加密技術在 Tink 中會顯示為一對原始物件：
- 使用 HybridEncrypt 進行加密
- 用於解密的 HybridDecrypt
結構定義資訊參數
除了明文以外，混合式加密也接受額外的參數 context_info，這通常是從結構定義中隱含的公開資料，但應繫結至產生的密文。這表示密文可讓您確認背景資訊的完整性，但無法保證其安全性或真實性。實際背景資訊可以是空白或空值，但為了確保產生的密文正確解密，您必須提供相同的結構定義資訊值以進行解密。
具體實作混合型加密，可透過多種方式將背景資訊繫結至密文，例如：
- 將
context_info做為 AEAD 對稱加密的關聯資料輸入 (請參閱 RFC 5116)。 - 使用
context_info做為 HKDF 的「CtxInfo」輸入 (如果實作使用 HKDF 做為金鑰衍生函式，請參閱 RFC 5869)。
選擇金鑰類型
針對大部分用途，我們建議使用 DHKEM_X25519_HKDF_SHA256_HKDF_SHA256_AES_256_GCM 金鑰類型。這個金鑰類型會實作 RFC 9180 中指定的混合公開金鑰加密 (HPKE) 標準。HPKE 包含金鑰封裝機制 (KEM)、金鑰衍生函式 (KDF)，以及用於相關資料 (AEAD) 演算法的已驗證加密機制。
DHKEM_X25519_HKDF_SHA256_HKDF_SHA256_AES_256_GCM 專任員工：
- KEM：Curve25519 上的 Diffie–Hellman 使用 HKDF-SHA-256 衍生出共用密鑰。
- KDF：HKDF-SHA-256 擷取傳送者和接收方的背景資訊。
- AEAD：AES-256-GCM，以及根據 HPKE 標準產生的 12 位元組 Nonce。
其他支援的 HPKE 金鑰類型 (但不限於) 以下類型：
DHKEM_X25519_HKDF_SHA256_HKDF_SHA256_AES_128_GCMDHKEM_X25519_HKDF_SHA256_HKDF_SHA256_CHACHA20_POLY1305DHKEM_P256_HKDF_SHA256_HKDF_SHA256_AES_128_GCMDHKEM_P521_HKDF_SHA512_HKDF_SHA512_AES_256_GCM
如要進一步瞭解 KEM、KDF 和 AEAD 的演算法選擇，請參閱 RFC 9180。
雖然已不再建議使用，但 Tink 也支援某些 ECIES 變化版本，如 Victor Shoup 的 ISO 18033-2 標準所述。以下列出部分支援的 ECIES 索引鍵類型：
ECIES_P256_HKDF_HMAC_SHA256_AES128_GCMECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_GCMECIES_P256_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256ECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256
最少屬性
- 純文字和背景資訊可以有任意長度 (在 0..232 個位元組範圍內)
- 防範自動調整選擇的密文攻擊
- 128 位元安全防護機制，適用於橢圓曲線配置