我想建立及驗證 JWT

Tink 的 JWT 程式庫可建立及驗證 JSON Web Token (JWT)。

建立 JWT

在大多數情況下，我們建議使用 JwtPublicKeySign 基本體和 JWT_ES256 金鑰類型。

下列範例說明如何建立 JWT，以及如何將公開金鑰集轉換為 JWK 集格式。

C++

// An example for signing JSON Web Tokens (JWT).
#include <iostream>
#include <memory>
#include <ostream>
#include <string>
#include <utility>

#include "absl/flags/flag.h"
#include "absl/flags/parse.h"
#include "absl/log/check.h"
#include "absl/strings/string_view.h"
#include "absl/time/clock.h"
#include "absl/time/time.h"
#include "tink/config/global_registry.h"
#include "util/util.h"
#include "tink/jwt/jwt_public_key_sign.h"
#include "tink/jwt/jwt_signature_config.h"
#include "tink/jwt/raw_jwt.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, audience, "", "Expected audience in the token");
ABSL_FLAG(std::string, token_filename, "", "Path to the token file");

namespace {

using ::crypto::tink::JwtPublicKeySign;
using ::crypto::tink::KeysetHandle;
using ::crypto::tink::RawJwt;
using ::crypto::tink::RawJwtBuilder;
using ::crypto::tink::util::Status;
using ::crypto::tink::util::StatusOr;

void ValidateParams() {
  // ...
}

}  // namespace

namespace tink_cc_examples {

// JWT sign example CLI implementation.
Status JwtSign(const std::string& keyset_filename, absl::string_view audience,
               const std::string& token_filename) {
  Status result = crypto::tink::JwtSignatureRegister();
  if (!result.ok()) return result;

  // Read the keyset from file.
  StatusOr<std::unique_ptr<KeysetHandle>> keyset_handle =
      ReadJsonCleartextKeyset(keyset_filename);
  if (!keyset_handle.ok()) return keyset_handle.status();
  StatusOr<RawJwt> raw_jwt =
      RawJwtBuilder()
          .AddAudience(audience)
          .SetExpiration(absl::Now() + absl::Seconds(100))
          .Build();
  if (!raw_jwt.ok()) return raw_jwt.status();
  StatusOr<std::unique_ptr<JwtPublicKeySign>> jwt_signer =
      (*keyset_handle)
          ->GetPrimitive<crypto::tink::JwtPublicKeySign>(
              crypto::tink::ConfigGlobalRegistry());
  if (!jwt_signer.ok()) return jwt_signer.status();

  StatusOr<std::string> token = (*jwt_signer)->SignAndEncode(*raw_jwt);
  if (!token.ok()) return token.status();

  return WriteToFile(*token, token_filename);
}

}  // namespace tink_cc_examples

int main(int argc, char** argv) {
  absl::ParseCommandLine(argc, argv);

  ValidateParams();

  std::string keyset_filename = absl::GetFlag(FLAGS_keyset_filename);
  std::string audience = absl::GetFlag(FLAGS_audience);
  std::string token_filename = absl::GetFlag(FLAGS_token_filename);

  std::clog << "Using keyset in " << keyset_filename << " to ";
  std::clog << " generate and sign a token using audience '" << audience
            << "'; the resulting signature is written to " << token_filename
            << '\n';

  CHECK_OK(
      tink_cc_examples::JwtSign(keyset_filename, audience, token_filename));
  return 0;
}
jwt_sign.cc

Go

func Example_signAndVerify() {
	// A private keyset created with
	// "tinkey create-keyset --key-template=JWT_ES256 --out private_keyset.cfg".
	// Note that this keyset has the secret key information in cleartext.
	privateJSONKeyset := `{
		"primaryKeyId": 1742360595,
		"key": [
			{
				"keyData": {
					"typeUrl": "type.googleapis.com/google.crypto.tink.JwtEcdsaPrivateKey",
					"value": "GiBgVYdAPg3Fa2FVFymGDYrI1trHMzVjhVNEMpIxG7t0HRJGIiBeoDMF9LS5BDCh6YgqE3DjHwWwnEKEI3WpPf8izEx1rRogbjQTXrTcw/1HKiiZm2Hqv41w7Vd44M9koyY/+VsP+SAQAQ==",
					"keyMaterialType": "ASYMMETRIC_PRIVATE"
				},
				"status": "ENABLED",
				"keyId": 1742360595,
				"outputPrefixType": "TINK"
			}
		]
	}`

	// The corresponding public keyset created with
	// "tinkey create-public-keyset --in private_keyset.cfg"
	publicJSONKeyset := `{
		"primaryKeyId": 1742360595,
		"key": [
			{
				"keyData": {
					"typeUrl": "type.googleapis.com/google.crypto.tink.JwtEcdsaPublicKey",
					"value": "EAEaIG40E1603MP9RyoomZth6r+NcO1XeODPZKMmP/lbD/kgIiBeoDMF9LS5BDCh6YgqE3DjHwWwnEKEI3WpPf8izEx1rQ==",
					"keyMaterialType": "ASYMMETRIC_PUBLIC"
				},
				"status": "ENABLED",
				"keyId": 1742360595,
				"outputPrefixType": "TINK"
			}
		]
	}`

	// 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 JWT Signer primitive from privateKeysetHandle.
	signer, err := jwt.NewSigner(privateKeysetHandle)
	if err != nil {
		log.Fatal(err)
	}

	// Use the primitive to create and sign a token. In this case, the primary key of the
	// keyset will be used (which is also the only key in this example).
	expiresAt := time.Now().Add(time.Hour)
	audience := "example audience"
	subject := "example subject"
	rawJWT, err := jwt.NewRawJWT(&jwt.RawJWTOptions{
		Audience:  &audience,
		Subject:   &subject,
		ExpiresAt: &expiresAt,
	})
	if err != nil {
		log.Fatal(err)
	}
	token, err := signer.SignAndEncode(rawJWT)
	if err != nil {
		log.Fatal(err)
	}

	// 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 Verifier primitive from publicKeysetHandle.
	verifier, err := jwt.NewVerifier(publicKeysetHandle)
	if err != nil {
		log.Fatal(err)
	}

	// Verify the signed token.
	validator, err := jwt.NewValidator(&jwt.ValidatorOpts{ExpectedAudience: &audience})
	if err != nil {
		log.Fatal(err)
	}
	verifiedJWT, err := verifier.VerifyAndDecode(token, validator)
	if err != nil {
		log.Fatal(err)
	}

	// Extract subject claim from the token.
	if !verifiedJWT.HasSubject() {
		log.Fatal(err)
	}
	extractedSubject, err := verifiedJWT.Subject()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(extractedSubject)
	// Output: example subject
}
jwt_test.go

Java

package jwt;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.crypto.tink.InsecureSecretKeyAccess;
import com.google.crypto.tink.KeysetHandle;
import com.google.crypto.tink.RegistryConfiguration;
import com.google.crypto.tink.TinkJsonProtoKeysetFormat;
import com.google.crypto.tink.jwt.JwtPublicKeySign;
import com.google.crypto.tink.jwt.JwtSignatureConfig;
import com.google.crypto.tink.jwt.RawJwt;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.Instant;

/**
 * A command-line utility for signing JSON Web Tokens (JWTs).
 *
 * <p>It loads cleartext private keys from disk - this is not recommended!
 *
 * <p>It requires the following arguments:
 *
 * <ul>
 *   <li>private-keyset-file: Name of the input file containing the private keyset.
 *   <li>audience: The audience claim to be used in the token
 *   <li>token-file: name of the output file containing the signed JWT.
 */
public final class JwtSign {
  public static void main(String[] args) throws Exception {
    if (args.length != 3) {
      System.err.printf("Expected 3 parameters, got %d\n", args.length);
      System.err.println("Usage: java JwtSign private-keyset-file audience token-file");
      System.exit(1);
    }

    Path privateKeysetFile = Paths.get(args[0]);
    String audience = args[1];
    Path tokenFile = Paths.get(args[2]);

    // Register all JWT signature key types with the Tink runtime.
    JwtSignatureConfig.register();

    // Read the private keyset into a KeysetHandle.
    KeysetHandle privateKeysetHandle =
        TinkJsonProtoKeysetFormat.parseKeyset(
            new String(Files.readAllBytes(privateKeysetFile), UTF_8),
            InsecureSecretKeyAccess.get());

    // Get the primitive.
    JwtPublicKeySign signer =
        privateKeysetHandle.getPrimitive(RegistryConfiguration.get(), JwtPublicKeySign.class);

    // Use the primitive to sign a token that expires in 100 seconds.
    RawJwt rawJwt =
        RawJwt.newBuilder()
            .addAudience(audience)
            .setExpiration(Instant.now().plusSeconds(100))
            .build();
    String signedToken = signer.signAndEncode(rawJwt);
    Files.write(tokenFile, signedToken.getBytes(UTF_8));
  }

  private JwtSign() {}
}
JwtSign.java

Python

"""A utility for creating and signing JSON Web Tokens (JWT).

It loads cleartext keys from disk - this is not recommended!
"""

import datetime

from absl import app
from absl import flags
from absl import logging
import tink
from tink import jwt
from tink import secret_key_access


_PRIVATE_KEYSET_PATH = flags.DEFINE_string(
    'private_keyset_path', None,
    'Path to the keyset used for the JWT signature operation.')
_AUDIENCE = flags.DEFINE_string('audience', None,
                                'Audience to be used in the token')
_TOKEN_PATH = flags.DEFINE_string('token_path', None, 'Path to the token file.')


def main(argv):
  del argv  # Unused.

  # Initialise Tink
  jwt.register_jwt_signature()

  # Read the keyset into a KeysetHandle
  with open(_PRIVATE_KEYSET_PATH.value, 'rt') as keyset_file:
    try:
      text = keyset_file.read()
      keyset_handle = tink.json_proto_keyset_format.parse(
          text, secret_key_access.TOKEN
      )
    except tink.TinkError as e:
      logging.exception('Error reading keyset: %s', e)
      return 1

  now = datetime.datetime.now(tz=datetime.timezone.utc)

  # Get the JwtPublicKeySign primitive
  try:
    jwt_sign = keyset_handle.primitive(jwt.JwtPublicKeySign)
  except tink.TinkError as e:
    logging.exception('Error creating JwtPublicKeySign: %s', e)
    return 1

  # Create token
  raw_jwt = jwt.new_raw_jwt(
      audiences=[_AUDIENCE.value],
      expiration=now + datetime.timedelta(seconds=100))
  token = jwt_sign.sign_and_encode(raw_jwt)
  with open(_TOKEN_PATH.value, 'wt') as token_file:
    token_file.write(token)
  logging.info('Token has been written to %s', _TOKEN_PATH.value)


if __name__ == '__main__':
  flags.mark_flags_as_required(
      ['private_keyset_path', 'audience', 'token_path'])
  app.run(main)
jwt_sign_cli.py

分享公開金鑰集的常見方式是使用 JWK 集格式。以下範例說明如何將公開金鑰集轉換為 JWK 集格式。

C++

// An example for converting a Tink keyset with public keys into a JWK set.
#include <iostream>
#include <memory>
#include <ostream>
#include <string>

#include "absl/flags/flag.h"
#include "absl/flags/parse.h"
#include "absl/log/check.h"
#include "util/util.h"
#include "tink/jwt/jwk_set_converter.h"
#include "tink/jwt/jwt_signature_config.h"
#include "tink/keyset_handle.h"
#include "tink/util/status.h"

ABSL_FLAG(std::string, public_keyset_filename, "",
          "Public keyset file in Tink's JSON format");
ABSL_FLAG(std::string, public_jwk_set_filename, "",
          "Path to the output public JWK set file");

namespace {

using ::crypto::tink::JwkSetFromPublicKeysetHandle;
using ::crypto::tink::KeysetHandle;
using ::crypto::tink::util::Status;
using ::crypto::tink::util::StatusOr;

void ValidateParams() {
  // ...
}

}  // namespace

namespace tink_cc_examples {

Status JwtGeneratePublicJwkSet(const std::string& public_keyset_filename,
                               const std::string& public_jwk_set_filename) {
  Status result = crypto::tink::JwtSignatureRegister();
  if (!result.ok()) return result;

  StatusOr<std::unique_ptr<KeysetHandle>> keyset_handle =
      ReadJsonCleartextKeyset(public_keyset_filename);
  if (!keyset_handle.ok()) return keyset_handle.status();

  StatusOr<std::string> public_jwk_set =
      JwkSetFromPublicKeysetHandle(**keyset_handle);
  if (!public_jwk_set.ok()) return keyset_handle.status();

  return WriteToFile(*public_jwk_set, public_jwk_set_filename);
}

}  // namespace tink_cc_examples

int main(int argc, char** argv) {
  absl::ParseCommandLine(argc, argv);

  ValidateParams();

  std::string public_keyset_filename =
      absl::GetFlag(FLAGS_public_keyset_filename);
  std::string public_jwk_set_filename =
      absl::GetFlag(FLAGS_public_jwk_set_filename);

  std::clog << "Convert public keyset in " << public_keyset_filename << " to ";
  std::clog << " to JWK set format; the result is written to "
            << public_jwk_set_filename << '\n';

  CHECK_OK(tink_cc_examples::JwtGeneratePublicJwkSet(public_keyset_filename,
                                                     public_jwk_set_filename));
  return 0;
}
jwt_generate_public_jwk_set.cc

Go

func Example_generateJWKS() {
	// A Tink keyset in JSON format with one JWT public key.
	publicJSONKeyset := `{
		"primaryKeyId": 1742360595,
		"key": [
			{
				"keyData": {
					"typeUrl": "type.googleapis.com/google.crypto.tink.JwtEcdsaPublicKey",
					"value": "EAEaIG40E1603MP9RyoomZth6r+NcO1XeODPZKMmP/lbD/kgIiBeoDMF9LS5BDCh6YgqE3DjHwWwnEKEI3WpPf8izEx1rQ==",
					"keyMaterialType": "ASYMMETRIC_PUBLIC"
				},
				"status": "ENABLED",
				"keyId": 1742360595,
				"outputPrefixType": "TINK"
			}
		]
	}`

	// 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)
	}

	// Create a publicJWKset from publicKeysetHandle.
	publicJWKset, err := jwt.JWKSetFromPublicKeysetHandle(publicKeysetHandle)
	if err != nil {
		log.Fatal(err)
	}

	// Remove whitespace so that we can compare it to the expected string.
	compactPublicJWKset := &bytes.Buffer{}
	err = json.Compact(compactPublicJWKset, publicJWKset)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(compactPublicJWKset.String())
	// Output:
	// {"keys":[{"alg":"ES256","crv":"P-256","key_ops":["verify"],"kid":"Z9pQEw","kty":"EC","use":"sig","x":"bjQTXrTcw_1HKiiZm2Hqv41w7Vd44M9koyY_-VsP-SA","y":"XqAzBfS0uQQwoemIKhNw4x8FsJxChCN1qT3_IsxMda0"}]}
}
jwt_test.go

Java

package jwt;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.crypto.tink.InsecureSecretKeyAccess;
import com.google.crypto.tink.KeysetHandle;
import com.google.crypto.tink.TinkJsonProtoKeysetFormat;
import com.google.crypto.tink.jwt.JwkSetConverter;
import com.google.crypto.tink.jwt.JwtSignatureConfig;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

/**
 * A command-line example for generating the public JWT keyset in JWK set format.
 *
 * <p>It loads cleartext private keys from disk - this is not recommended!
 *
 * <p>It requires the following arguments:
 *
 * <ul>
 *   <li>private-keyset-file: Name of the input file containing the private keyset.
 *   <li>public-jwkset-file: Name of the output file containing the public key in JWK set format.
 */
public final class JwtGeneratePublicJwkSet {
  public static void main(String[] args) throws Exception {
    if (args.length != 2) {
      System.err.printf("Expected 2 parameters, got %d\n", args.length);
      System.err.println(
          "Usage: java JwtGeneratePublicJwkSet private-keyset-file public-jwk-set-file");
      System.exit(1);
    }

    Path privateKeysetFile = Paths.get(args[0]);
    Path publicJwkSetFile = Paths.get(args[1]);

    // Register all JWT signature key types with the Tink runtime.
    JwtSignatureConfig.register();

    // Read the keyset into a KeysetHandle.
    KeysetHandle privateKeysetHandle =
        TinkJsonProtoKeysetFormat.parseKeyset(
            new String(Files.readAllBytes(privateKeysetFile), UTF_8),
            InsecureSecretKeyAccess.get());

    // Export the public keyset as JWK set.
    String publicJwkSet =
        JwkSetConverter.fromPublicKeysetHandle(privateKeysetHandle.getPublicKeysetHandle());
    Files.write(publicJwkSetFile, publicJwkSet.getBytes(UTF_8));
  }

  private JwtGeneratePublicJwkSet() {}
}
JwtGeneratePublicJwkSet.java

Python

"""A utility for generating the public JWK set from the public keyset.
"""

from absl import app
from absl import flags
from absl import logging
import tink
from tink import jwt


_PUBLIC_KEYSET_PATH = flags.DEFINE_string(
    'public_keyset_path', None,
    'Path to the public keyset in Tink JSON format.')
_PUBLIC_JWK_SET_PATH = flags.DEFINE_string(
    'public_jwk_set_path', None, 'Path to public keyset in JWK format.')


def main(argv):
  del argv  # Unused.

  # Initialise Tink
  jwt.register_jwt_signature()

  # Read the keyset into a KeysetHandle
  with open(_PUBLIC_KEYSET_PATH.value, 'rt') as keyset_file:
    try:
      text = keyset_file.read()
      public_keyset_handle = tink.json_proto_keyset_format.parse_without_secret(
          text
      )
    except tink.TinkError as e:
      logging.exception('Error reading keyset: %s', e)
      return 1

  # Export Public Keyset as JWK set
  public_jwk_set = jwt.jwk_set_from_public_keyset_handle(public_keyset_handle)
  with open(_PUBLIC_JWK_SET_PATH.value, 'wt') as public_jwk_set_file:
    public_jwk_set_file.write(public_jwk_set)
  logging.info('The public JWK set has been written to %s',
               _PUBLIC_JWK_SET_PATH.value)


if __name__ == '__main__':
  flags.mark_flags_as_required(['public_keyset_path', 'public_jwk_set_path'])
  app.run(main)
jwt_generate_public_jwk_set.py

驗證 JWT

我們建議在大多數用途中使用 JwtPublicKeyVerify 基本體，並搭配 JWT_ES256 金鑰類型。

下列範例說明如何使用 JWK 集格式的公開金鑰集驗證 JWT。這種格式常用於與其他方共用公開金鑰集。

C++

// A utility for creating, signing and verifying JSON Web Tokens (JWT).
#include <iostream>
#include <memory>
#include <ostream>
#include <string>
#include <utility>

#include "absl/flags/flag.h"
#include "absl/flags/parse.h"
#include "absl/log/check.h"
#include "absl/strings/string_view.h"
#include "tink/config/global_registry.h"
#include "util/util.h"
#include "tink/jwt/jwk_set_converter.h"
#include "tink/jwt/jwt_public_key_verify.h"
#include "tink/jwt/jwt_signature_config.h"
#include "tink/jwt/jwt_validator.h"
#include "tink/keyset_handle.h"
#include "tink/util/status.h"

ABSL_FLAG(std::string, jwk_set_filename, "", "Path to the JWK set file");
ABSL_FLAG(std::string, audience, "", "Expected audience in the token");
ABSL_FLAG(std::string, token_filename, "", "Path to the token file");

namespace {

using ::crypto::tink::JwkSetToPublicKeysetHandle;
using ::crypto::tink::JwtPublicKeyVerify;
using ::crypto::tink::JwtValidator;
using ::crypto::tink::KeysetHandle;
using ::crypto::tink::util::Status;
using ::crypto::tink::util::StatusOr;

void ValidateParams() {
  // ...
}

}  // namespace

namespace tink_cc_examples {

// JWT verify example CLI implementation.
Status JwtVerify(const std::string& jwk_set_filename,
                 absl::string_view audience,
                 const std::string& token_filename) {
  Status result = crypto::tink::JwtSignatureRegister();
  if (!result.ok()) return result;

  // Read the JWK set from file and convert it.
  StatusOr<std::string> jwk_set = ReadFile(jwk_set_filename);
  if (!jwk_set.ok()) return jwk_set.status();
  StatusOr<std::unique_ptr<KeysetHandle>> keyset_handle =
      JwkSetToPublicKeysetHandle(*jwk_set);

  // Read the token.
  StatusOr<std::string> token = ReadFile(token_filename);
  if (!token.ok()) return token.status();

  StatusOr<JwtValidator> validator =
      crypto::tink::JwtValidatorBuilder().ExpectAudience(audience).Build();
  if (!validator.ok()) return validator.status();

  StatusOr<std::unique_ptr<JwtPublicKeyVerify>> jwt_verifier =
      (*keyset_handle)
          ->GetPrimitive<crypto::tink::JwtPublicKeyVerify>(
              crypto::tink::ConfigGlobalRegistry());
  if (!jwt_verifier.ok()) return jwt_verifier.status();

  return (*jwt_verifier)->VerifyAndDecode(*token, *validator).status();
}

}  // namespace tink_cc_examples

int main(int argc, char** argv) {
  absl::ParseCommandLine(argc, argv);

  ValidateParams();

  std::string jwk_set_filename = absl::GetFlag(FLAGS_jwk_set_filename);
  std::string audience = absl::GetFlag(FLAGS_audience);
  std::string token_filename = absl::GetFlag(FLAGS_token_filename);

  std::clog << "Using keyset in " << jwk_set_filename << " to ";
  std::clog << " verify a token with expected audience '" << audience << '\n';

  CHECK_OK(
      tink_cc_examples::JwtVerify(jwk_set_filename, audience, token_filename));
  return 0;
}
jwt_verify.cc

Go

func Example_verifyWithJWKS() {
	// A signed token with the subject 'example subject', audience 'example audience'.
	// and expiration on 2023-03-23.
	token := `eyJhbGciOiJFUzI1NiIsICJraWQiOiJaOXBRRXcifQ.eyJhdWQiOiJleGFtcGxlIGF1ZGllbmNlIiwgImV4cCI6MTY3OTUzMzIwMCwgInN1YiI6ImV4YW1wbGUgc3ViamVjdCJ9.ZvI0T84fJ1aouiB7n62kHOmbm0Hpfiz0JtYs15XVDT8KyoVYZ8hu_DGJUN47BqZIbuOI-rdu9TxJvutj8uF3Ow`

	// A public keyset in the JWK set format.
	publicJWKset := `{
		"keys":[
			{
				"alg":"ES256",
				"crv":"P-256",
				"key_ops":["verify"],
				"kid":"Z9pQEw",
				"kty":"EC",
				"use":"sig",
				"x":"bjQTXrTcw_1HKiiZm2Hqv41w7Vd44M9koyY_-VsP-SA",
				"y":"XqAzBfS0uQQwoemIKhNw4x8FsJxChCN1qT3_IsxMda0"
			}
		]
	}`

	// Create a keyset handle from publicJWKset.
	publicKeysetHandle, err := jwt.JWKSetToPublicKeysetHandle([]byte(publicJWKset))
	if err != nil {
		log.Fatal(err)
	}

	// Retrieve the Verifier primitive from publicKeysetHandle.
	verifier, err := jwt.NewVerifier(publicKeysetHandle)
	if err != nil {
		log.Fatal(err)
	}

	// Verify the signed token. For this example, we use a fixed date. Usually, you would
	// either not set FixedNow, or set it to the current time.
	audience := "example audience"
	validator, err := jwt.NewValidator(&jwt.ValidatorOpts{
		ExpectedAudience: &audience,
		FixedNow:         time.Date(2023, 3, 23, 0, 0, 0, 0, time.UTC),
	})
	if err != nil {
		log.Fatal(err)
	}
	verifiedJWT, err := verifier.VerifyAndDecode(token, validator)
	if err != nil {
		log.Fatal(err)
	}

	// Extract subject claim from the token.
	if !verifiedJWT.HasSubject() {
		log.Fatal(err)
	}
	extractedSubject, err := verifiedJWT.Subject()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(extractedSubject)
	// Output: example subject
}
jwt_test.go

Java

package jwt;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.crypto.tink.KeysetHandle;
import com.google.crypto.tink.RegistryConfiguration;
import com.google.crypto.tink.jwt.JwkSetConverter;
import com.google.crypto.tink.jwt.JwtPublicKeyVerify;
import com.google.crypto.tink.jwt.JwtSignatureConfig;
import com.google.crypto.tink.jwt.JwtValidator;
import com.google.crypto.tink.jwt.VerifiedJwt;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.List;

/**
 * A command-line utility for verifying JSON Web Tokens (JWTs).
 *
 * <p>It requires the following arguments:
 *
 * <ul>
 *   <li>public-jwkset-file: Name of the input file containing the public keyset in JWK set format.
 *   <li>audience: The audience claim to be used in the token
 *   <li>token-file: name of the input file containing the signed JWT.
 */
public final class JwtVerify {
  public static void main(String[] args) throws Exception {
    if (args.length != 3) {
      System.err.printf("Expected 3 parameters, got %d\n", args.length);
      System.err.println(
          "Usage: java JwtVerify public-jwk-set-file audience token-file");
      System.exit(1);
    }

    Path publicJwkSetFile = Paths.get(args[0]);
    String audience = args[1];
    Path tokenFile = Paths.get(args[2]);

    // Register all JWT signature key types with the Tink runtime.
    JwtSignatureConfig.register();

    // Read the public keyset in JWK set format into a KeysetHandle.
    KeysetHandle publicKeysetHandle =
        JwkSetConverter.toPublicKeysetHandle(
            new String(Files.readAllBytes(publicJwkSetFile), UTF_8));

    List<String> lines = Files.readAllLines(tokenFile, UTF_8);
    if (lines.size() != 1) {
      System.err.printf("The signature file should contain only one line,  got %d", lines.size());
      System.exit(1);
    }
    String signedToken = lines.get(0).trim();

    // Get the primitive.
    JwtPublicKeyVerify verifier =
        publicKeysetHandle.getPrimitive(RegistryConfiguration.get(), JwtPublicKeyVerify.class);

    // Use the primitive to verify a token.
    JwtValidator validator = JwtValidator.newBuilder().expectAudience(audience).build();
    VerifiedJwt verifiedJwt = verifier.verifyAndDecode(signedToken, validator);
    long seconds = ChronoUnit.SECONDS.between(Instant.now(), verifiedJwt.getExpiration());
    System.out.println("Token is valid and expires in " + seconds + " seconds.");
  }

  private JwtVerify() {}
}
JwtVerify.java

Python

"""A utility for verifying Json Web Tokens (JWT)."""

import datetime

from absl import app
from absl import flags
from absl import logging
import tink
from tink import jwt


FLAGS = flags.FLAGS

_PUBLIC_JWK_SET_PATH = flags.DEFINE_string(
    'public_jwk_set_path', None, 'Path to public keyset in JWK set format.')
_AUDIENCE = flags.DEFINE_string('audience', None,
                                'Audience to be used in the token')
_TOKEN_PATH = flags.DEFINE_string('token_path', None,
                                  'Path to the signature file.')


def main(argv):
  del argv  # Unused.

  # Initialise Tink
  jwt.register_jwt_signature()

  with open(_PUBLIC_JWK_SET_PATH.value, 'rt') as public_jwk_set_file:
    try:
      text = public_jwk_set_file.read()
      keyset_handle = jwt.jwk_set_to_public_keyset_handle(text)
    except tink.TinkError as e:
      logging.exception('Error reading public JWK set: %s', e)
      return 1

  now = datetime.datetime.now(tz=datetime.timezone.utc)
  try:
    jwt_verify = keyset_handle.primitive(jwt.JwtPublicKeyVerify)
  except tink.TinkError as e:
    logging.exception('Error creating JwtPublicKeyVerify: %s', e)
    return 1

  # Verify token
  with open(_TOKEN_PATH.value, 'rt') as token_file:
    token = token_file.read()
  validator = jwt.new_validator(expected_audience=_AUDIENCE.value)
  try:
    verified_jwt = jwt_verify.verify_and_decode(token, validator)
    expires_in = verified_jwt.expiration() - now
    logging.info('Token is valid and expires in %s seconds', expires_in.seconds)
    return 0
  except tink.TinkError as e:
    logging.info('JWT verification failed: %s', e)
    return 1


if __name__ == '__main__':
  flags.mark_flags_as_required(['audience', 'token_path'])
  app.run(main)
jwt_verify_cli.py

JSON Web Token (JWT)

Tink 支援產生及驗證 JWT，這是網路上廣為使用的標準。Tink 的 JWT 實作提供 RFC 7519 中定義的 JWT 標準子集，Tink 團隊認為這些標準可安全使用，且非常適合 Tink 程式庫。

Tink 不支援很少使用或難以正確使用的標準部分。限制如下：

• Tink 僅支援 JWS Compact Serialization 格式。不支援 JWS JSON 序列化和 JWE。
• Tink 不支援 alg 標頭中的 None 值。
• Tink 僅支援 typ、alg 和 kid 標頭。系統不支援其他標頭。
• Tink 不允許在驗證簽章或 MAC 之前剖析權杖。

JWT 簽章

如果權杖是由不同實體產生及驗證，則應搭配使用原始值 JwtPublicKeySign 和 JwtPublicKeyVerify 的非對稱金鑰。私密金鑰用於產生權杖，公開金鑰則用於驗證權杖。這些基本體支援的演算法包括：ES256、ES384、ES512、RS256、RS384、RS512、PS256、PS384 和 PS512。

選擇金鑰類型

JWT 簽章使用的金鑰類型與 Tink 中的一般數位簽章不同。這是因為部分中繼資料 (例如 alg 和 kid) 必須與金鑰一併儲存。

我們建議在多數情況下使用 JWT_ES256。使用這類金鑰產生的權杖一律會有 kid 標頭。如果偏好稍微短一點的權杖，且不需要 kid 標頭，請選擇 JWT_ES256_RAW 金鑰類型。如要查看所有支援的鍵類型，請參閱「支援的鍵類型」。

公開金鑰集發布

Tink 允許公開金鑰集轉換為 RFC 7517 中定義的 JWK 集格式，以及從該格式轉換，而大多數 JWT 程式庫都能理解這種格式。

注意： Tink 的 JSON 金鑰集序列化格式「並非」 JWK 集，其他程式庫可能無法讀取。

Tink 不支援以任何其他格式匯出公開 JWT 金鑰。這是因為其他格式不含驗證時使用的 alg 和 kid 中繼資料，因此較容易發生錯誤，且可能難以輪替金鑰。

最好不要只分享一次公開金鑰集，而是提供自動更新公開金鑰集的方法。(否則很難輪替為新金鑰)。通常的做法是在受信任且安全的網址上發布公開金鑰集。驗證權杖的伺服器必須定期從該網址重新擷取公開金鑰集，例如每天一次。如要輪替金鑰，請至少提前一天將新的公開金鑰新增至公開金鑰組，再用來簽署權杖。否則，伺服器仍會使用舊版公開金鑰集，因此會拒絕以新私密金鑰簽署的新權杖。

注意： 部分實作方式會在收到含有不明 kid 標頭的權杖後，立即重新擷取公開金鑰。由於權杖在驗證前不會經過剖析，因此無法在 Tink 中導入這項邏輯。我們不建議您這麼做，因為如果傳送含有隨機 kid 標頭的惡意權杖，可能會導致金鑰集網址收到大量額外要求。

JWT MAC

Tink 也支援使用對稱式金鑰的 JWT，並提供 JwtMac 基本型別。只有在權杖是由同一實體產生及驗證時，才使用這個基本類型。這項基本功能支援的演算法為 HS256、HS384 和 HS512。

選擇金鑰類型

JWT MAC 金鑰類型與一般 MAC 金鑰類型不同。我們建議在多數情況下使用 JWT_HS256。