如何使用 java 验证由 keycloak 签名的 JWT

Question

我有 keyCloack 生成的 JWT，RS256 类似这样

样本：

eyJhbGciOwia2lkIiA6ICJtSG1lajZEc09GaV9MejdSMjhzWjdMWkxBRXVzIn0.eyBzA2MzQvOTcwNjM1L1NNUyIsIi83Ni83NS9TTVMiXSwicHJYW1lIjoidGVzdDEwNUB1c2VyLmNvbSIsInVzZXJOYW1lIjoidGVzdDEwNUB1c2VyLmNvbSIsInVzZXJJZCI6IjU4NDM2NmQ4LWU5NDItNGJhNy04OGVlLWMyZTBlODhmZmY5ZCIsImVtYWlsIjoidGVzdDEwNUB1c2VyLmNvbSJ9.4TgC1MLyUl1P36oD6FafBCh0peEaCBmkyLheVjnlBu8uePl9xgEN6wdeWe

我需要使用 keycloack 证书解码和验证此令牌。

我可以通过 api 访问 keycloack 证书。

https://xxx.xxx.com.tr/auth/realms/myrealm/protocol/openid-connect/certs

在响应中，我有 x5c 字段。

{
    "keys": [
        {
            "kid": "j6DsCpPOz1RXJhtPR28sZ7LZLAEus",
            "kty": "RSA",
            "alg": "RS256",
            "use": "sig",
            "n": "m0oTFvyLhLGIciXfndxc7uhIKE2-q9nJQKByd0FVYe8Cd4CHDpTzzcYdPWRR-1_VKQ75wqpybRt-LnnTKPNCXrPtPDRn2GFihtYyyO8VjeVtnz-iYJJAHkdp25HlMtX9l-VjnQX9s70-lbMmCVCRTerw",
            "e": "AQAB",
            "x5c": [
                "MIICnTCCAYUCBgFzh2ZkQzANBgkqhkiG9w0BAQ50F/bO9PpWzJglQkU3q8CAwEAATANBgkqhkiG9w01faO/9ZzyiLMLsorUKzYPNAxc7Q9rLE0J2MCWfapx3/E4yyNjISuB1HpS5iF44OEhGHJlw7JQeogcZat0enB8yyXtP/cgBhCnrWwfugX8rHsWfHakBGdsoazR9w=="
            ],
            "x5t": "YF6LE97opzsTtD-yLNx9-Lo",
            "x5t#S256": "SdNCfMbCjvcq-JY3iiGAj7De9Hal_0Cck-bDFK3Ow"
        }
    ]
}

如果我将 x5c 部分放在 ----CERTIFICATE----- 标签中，我可以通过 https://jwt.io/ 验证这个 jwt

如何在 Java 中验证同样的事情？

我尝试了几件事但都失败了。

Answer 1

我认为您可以为此使用 jose4j 库。

HttpsJwks httpsJkws = new HttpsJwks("https://xxx.xxx.com.tr/auth/realms/myrealm/protocol/openid-connect/certs");
HttpsJwksVerificationKeyResolver httpsJwksKeyResolver = new HttpsJwksVerificationKeyResolver(httpsJkws);


// Use JwtConsumerBuilder to construct an appropriate JwtConsumer, which will
// be used to validate and process the JWT. But, in this case, provide it with
// the HttpsJwksVerificationKeyResolver instance rather than setting the
// verification key explicitly.

jwtConsumer = new JwtConsumerBuilder()
    // ... other set up of the JwtConsumerBuilder ...
    .setVerificationKeyResolver(httpsJwksKeyResolver)
    // ...
    .build();

Answer 2

我找到路了。

首先，我们需要登录keycloack控制台，您可以访问与领域相关的public密钥。

现在您拥有来自 keycloak 的 public密钥和来自用户的 JWT。

需要先导入相关库

<dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-api</artifactId>
            <version>0.11.2</version>
        </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-impl</artifactId>
            <version>0.11.2</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt-jackson</artifactId>
            <version>0.11.2</version>
            <scope>runtime</scope>
        </dependency>

之后就是逻辑了。

String token = "ghfghfdhdhdfhdfghdhdfhdfhdfhhdf";
String rsaPublicKey = "awdasdsadaefafafaef5df65d4f";
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(Base64.getDecoder().decode(rsaPublicKey));
KeyFactory kf = KeyFactory.getInstance("RSA");
PublicKey = kf.generatePublic(keySpec);

我们有public密钥，我们需要验证它

Jws<Claims> jwt = null;
try {
    jwt = Jwts.parserBuilder()
                        .setSigningKey(publicKey)
                        .build()
                        .parseClaimsJws(token);
            } catch (Exception e) {
                // if you get error, that means token is invalid.
            }

如何使用 java 验证由 keycloak 签名的 JWT

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