Question

我是密码学的新手。我正在研究POC来加密和解密字符串。当我解密加密的字符串时，它有时可以工作，但有时会抛出标签不匹配错误。我想念什么吗？

这是我的代码：

EncryptionServiceImpl.java

public class EncryptionServiceImpl {
    private static final Logger log = LoggerFactory.getLogger("EncryptionServiceImpl");

    private final KeysetHandle keysetHandle;
    private final Aead aead;

    public EncryptionServiceImpl() throws GeneralSecurityException {
        AeadConfig.register();
        this.keysetHandle = KeysetHandle.generateNew(AeadKeyTemplates.AES128_GCM);
        aead = AeadFactory.getPrimitive(keysetHandle);
    }

    public String encrypt(String text) throws GeneralSecurityException {

        log.info(String.format("Encrypting %s", text));
        byte[] plainText = text.getBytes();
        byte[] additionalData = "masterkey".getBytes();
        byte[] cipherText = aead.encrypt(plainText,additionalData);

        String output = new String(cipherText);

        log.info(String.format("The encrypted text: %s", output));
        return output;
    }

    public String decrypt(String text) throws GeneralSecurityException {

        log.info(String.format("Decrypting %s", text));

        byte[] cipherText = text.getBytes();
        byte[] additionalData = "masterkey".getBytes();
        byte[] decipheredData = aead.decrypt(cipherText,additionalData);

        String output = new String(decipheredData);

        log.info(String.format("The decrypted text: %s", output));
        return output;
    }

}

EncryptionServiceImplTest.java

public class EncryptionServiceImplTest {

    @Test
    public void encrypt() throws IOException, GeneralSecurityException {
        EncryptionServiceImpl encryptionService = new EncryptionServiceImpl();
        String encryptedText = encryptionService.encrypt("Hello World");
        assertThat(encryptedText, Matchers.notNullValue());
    }

    @Test
    public void decrypt() throws IOException, GeneralSecurityException {
        EncryptionServiceImpl encryptionService = new EncryptionServiceImpl();

        String encryptedText = encryptionService.encrypt("Hello World");
        String decrypedText = encryptionService.decrypt(encryptedText);

        assertThat(decrypedText, Matchers.is("Hello World"));
    }
}

例外： INFO：密文前缀与密钥匹配，但无法解密：javax.crypto.AEADBadTagException：标记不匹配！ com.encryption.api.service.EncryptionServiceImplTest>解密失败

java.security.GeneralSecurityException at EncryptionServiceImplTest.java:25

解密失败 java.security.GeneralSecurityException：解密失败在com.google.crypto.tink.aead.AeadFactory $ 1.decrypt（AeadFactory.java:109）在com.encryption.api.service.EncryptionServiceImpl.decrypt（EncryptionServiceImpl.java:53）在com.encryption.api.service.EncryptionServiceImplTest.decrypt（EncryptionServiceImplTest.java:25）在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）在org.junit.runners.model.FrameworkMethod $ 1.runReflectiveCall（FrameworkMethod.java:50）在org.junit.internal.runners.model.ReflectiveCallable.run（ReflectiveCallable.java:12）在org.junit.runners.model.FrameworkMethod.invokeExplosively（FrameworkMethod.java:47）在org.junit.internal.runners.statements.InvokeMethod.evaluate（InvokeMethod.java:17）在org.junit.runners.ParentRunner.runLeaf（ParentRunner.java:325）在org.junit.runners.BlockJUnit4ClassRunner.runChild（BlockJUnit4ClassRunner.java:78）在org.junit.runners.BlockJUnit4ClassRunner.runChild（BlockJUnit4ClassRunner.java:57）在org.junit.runners.ParentRunner $ 3.run（ParentRunner.java:290）在org.junit.runners.ParentRunner $ 1.schedule（ParentRunner.java:71）在org.junit.runners.ParentRunner.runChildren（ParentRunner.java:288）在org.junit.runners.ParentRunner.access $ 000（ParentRunner.java:58）在org.junit.runners.ParentRunner上$ 2.evaluate（ParentRunner.java:268）在org.junit.runners.ParentRunner.run（ParentRunner.java:363）在org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass（JUnitTestClassExecuter.java:114）在org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute（JUnitTestClassExecuter.java:57）在org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass（JUnitTestClassProcessor.java:66）在org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass（SuiteTestClassProcessor.java:51）在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）在org.gradle.internal.dispatch.ReflectionDispatch.dispatch（ReflectionDispatch.java:35）在org.gradle.internal.dispatch.ReflectionDispatch.dispatch（ReflectionDispatch.java:24）在org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch（ContextClassLoaderDispatch.java:32）在org.gradle.internal.dispatch.ProxyDispatchAdapter $ DispatchingInvocationHandler.invoke（ProxyDispatchAdapter.java:93）在com.sun.proxy。$ Proxy1.processTestClass（未知来源）在org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass（TestWorker.java:108）在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）在org.gradle.internal.dispatch.ReflectionDispatch.dispatch（ReflectionDispatch.java:35）在org.gradle.internal.dispatch.ReflectionDispatch.dispatch（ReflectionDispatch.java:24）在org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection $ DispatchWrapper.dispatch（MessageHubBackedObjectConnection.java:146）在org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection $ DispatchWrapper.dispatch（MessageHubBackedObjectConnection.java:128）在org.gradle.internal.remote.internal.hub.MessageHub $ Handler.run（MessageHub.java:404）在org.gradle.internal.concurrent.ExecutorPolicy $ CatchAndRecordFailures.onExecute（ExecutorPolicy.java:63）在org.gradle.internal.concurrent.ManagedExecutorImpl $ 1.run（ManagedExecutorImpl.java:46）在java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1149）在java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:624）在org.gradle.internal.concurrent.ThreadFactoryImpl $ ManagedThreadRunnable.run（ThreadFactoryImpl.java:55）在java.lang.Thread.run（Thread.java:748）

1个测试完成，1个失败

Answer 1

如果加密消息的字节序列存储在字符串中，则必须使用适当的编码。适当意味着编码必须允许序列中的所有字节或字节组合。如果不是这种情况，则字节序列中的值会自动更改，并且在存储期间不会被注意。如果随后在解密过程中从字符串中重建了字节数组，则原始字节数组和重建的字节数组将不同，并且解密失败。 here对此进行了很好的解释。

由于AES-GCM为每种加密生成一个新的初始化向量，因此即使采用相同的明文，每种加密的加密消息也有所不同。

两者都导致一个事实，在您的示例中，加密有时有效，有时无效：只要字节序列与您使用的编码兼容，解密就起作用，否则无效。

如果要独立于编码，只需使用字节数组本身即可，即encrypt方法返回字节数组而不是字符串，类似地，返回字节数组而不是字符串传递给decrypt方法。

Answer 2

我修改了代码，但仍然看到对于相同的请求解密有时会失败。

public class Utils {
private static final Logger log = LoggerFactory.getLogger(Utils.class);
private Aead aead;
private static Utils utils;

private Utils() {
    try {
        AeadConfig.register();
        KeysetHandle keysetHandle = KeysetHandle.generateNew(AeadKeyTemplates.AES128_GCM);
        aead = AeadFactory.getPrimitive(keysetHandle);
    } catch (GeneralSecurityException e) {
        log.error(String.format("Error occured: %s",e.getMessage())).log();
    }
}

public static Utils getInstance() {
    if(null == utils) {
        utils = new Utils();
    }

    return utils;
}

public String encrypt(String text) throws GeneralSecurityException, UnsupportedEncodingException {
    byte[] plainText = text.getBytes("ISO-8859-1");
    byte[] additionalData = null;
    byte[] cipherText = aead.encrypt(plainText,additionalData);

    String output = Base64.getEncoder().encodeToString(cipherText);
    return output;
}

public String decrypt(String text) throws GeneralSecurityException, UnsupportedEncodingException {
    byte[] cipherText = Base64.getDecoder().decode(text);
    byte[] additionalData = null;
    byte[] decipheredData = aead.decrypt(cipherText,additionalData);

    String output = new String(decipheredData,"ISO-8859-1");
    return output;
}

}

Answer 3

当我在本地计算机上运行时，我也没有在代码中得到错误。但是当我部署在云（谷歌云），我开始看到错误。

这是我的Junit代码：

public class UtilsTest {

private static final Utils cryptographicUtils = Utils.getInstance();

@Test
public void encrypt() throws IOException, GeneralSecurityException {
    String encryptedText = cryptographicUtils.encrypt("Hello World");
    assertThat(encryptedText, Matchers.notNullValue());
}

@Test
public void decrypt() throws IOException, GeneralSecurityException {
    String encryptedText = cryptographicUtils.encrypt("Hello 123456");
    String decrypedText = cryptographicUtils.decrypt(encryptedText);

    assertThat(decrypedText, Matchers.is("Hello 123456"));
}

}

使用Google Tink库解密密钥时出现标签不匹配错误

3 个答案: