异常解包密钥：填充错误：解密错误

Question

我正在尝试解密文件 "test.txt.p7b"，该文件使用 JKS 中的证书加密。

我在调试代码时收到此错误。感谢有人可以解释为什么会出现此错误。是我的钥匙有问题还是我的代码有问题（大多数情况下，我相信是这样）。非常感谢

错误信息如下，

Exception in thread "main" org.bouncycastle.cms.CMSException: exception unwrapping key: bad padding: Decryption error
    at org.bouncycastle.cms.jcajce.JceKeyTransRecipient.extractSecretKey(Unknown Source)
    at org.bouncycastle.cms.jcajce.JceKeyTransEnvelopedRecipient.getRecipientOperator(Unknown Source)
    at org.bouncycastle.cms.KeyTransRecipientInformation.getRecipientOperator(Unknown Source)
    at org.bouncycastle.cms.RecipientInformation.getContentStream(Unknown Source)
    at org.bouncycastle.cms.RecipientInformation.getContent(Unknown Source)
    at TestingB.decryptData(TestingB.java:299)
    at TestingB.main(TestingB.java:161)
Caused by: org.bouncycastle.operator.OperatorException: bad padding: Decryption error
    at org.bouncycastle.operator.jcajce.JceAsymmetricKeyUnwrapper.generateUnwrappedKey(Unknown Source)
    ... 7 more
Caused by: javax.crypto.BadPaddingException: Decryption error
    at sun.security.rsa.RSAPadding.unpadV15(Unknown Source)
    at sun.security.rsa.RSAPadding.unpad(Unknown Source)
    at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
    at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)
    at javax.crypto.Cipher.doFinal(Cipher.java:2121)
    ... 8 more

这是我的解密代码。

    FileInputStream fIn = new FileInputStream(_keyStorePath);
    KeyStore keystore = KeyStore.getInstance("JKS");
    keystore.load(fIn, _password);
    PrivateKey key = (PrivateKey) keystore.getKey("def","123456".toCharArray());
    fIn.close();


    File file = new File("C:\1_Eclipse\1_CS\Encrypted\test.txt.p7b");
    FileInputStream fileInputStream = new FileInputStream(file);
    byte[] encryptedAndSignedByte = new byte[(int)file.length()];
    fileInputStream.read(encryptedAndSignedByte);
    fileInputStream.close();


    X509Certificate cert9 = (X509Certificate) keystore.getCertificate("abc");
    KeyTransRecipientId recId = new JceKeyTransRecipientId(cert9.getIssuerX500Principal(), cert9.getSerialNumber());

    CMSEnvelopedData enveloped = new CMSEnvelopedData(encryptedAndSignedByte);
    RecipientInformationStore recipients = enveloped.getRecipientInfos();
    RecipientInformation recipient = recipients.get(recId);
    JceKeyTransEnvelopedRecipient ter = new JceKeyTransEnvelopedRecipient(key);
    ter.setContentProvider(BouncyCastleProvider.PROVIDER_NAME);
    System.out.println("content : " + recipient.getContent(ter));

Answer 1

从这里我看不出哪里出了问题，但是错误发生在用RSA私钥解密对称密钥的过程中。

CMS 是一种容器格式。它包含处理或封装数据的方法。如果您有一个封装容器，则其中的数据不会直接使用 RSA public 密钥加密。相反，它是用随机对称密钥（通常称为数据密钥甚至会话密钥）加密的。然后使用 public 密钥加密此对称密钥。

RSA加密首先填充数据，然后用public指数进行模幂运算。解密包括使用私有指数和去填充的模幂运算。现在，无论数据或指数的值如何，模幂总是会成功。因此，如果数据或密钥无效，则填充异常是唯一的指示。

由于容器中的数据可能是有效的 - 如果不是，您会期望出现解码错误 - 私钥很可能与 public 密钥不匹配。它不排除 CMS 库的实现错误，但如果 CMS 库经过良好测试，我认为这种可能性相对较小。

所以我会怀疑你的密钥值而不是你的代码 - 当然也可能在读取或写入你的密钥的代码中有错误。

总而言之，我肯定会首先修复您代码中的流处理。仅仅创建一个 encryptedAndSignedByte 缓冲区并调用 read 一次是非常幼稚的，它可能不会 return 所有数据。

Answer 2

我修改了代码，还是出现同样的问题。我相信加密部分应该没有问题。

解密代码：

public static void decrypt(final InputStream is, OutputStream os, Key key, String providerName) throws Exception  {
        final InputStream bis = new BufferedInputStream(is, bufferSize);
        final OutputStream bos = new BufferedOutputStream(os, bufferSize);
        final Iterator  it = new CMSEnvelopedDataParser(bis).getRecipientInfos().getRecipients().iterator();
        if (it.hasNext()) {
            final RecipientInformation recipient = (RecipientInformation)it.next();
            JceKeyTransEnvelopedRecipient ter = new JceKeyTransEnvelopedRecipient((PrivateKey) key);
            final CMSTypedStream recData = recipient.getContentStream(ter);
            final InputStream ris = recData.getContentStream();
            fromInToOut(ris, bos);
        }
        os.close();
    }

主要class

new File("C:\1_Eclipse\1_CS\Encrypted\test_result.txt");
        FileOutputStream E_fileOuputStream = new FileOutputStream("C:\1_Eclipse\1_CS\Encrypted\test_result.txt"); 
        FileInputStream E_fileInputStream = new FileInputStream("C:\1_Eclipse\1_CS\Encrypted\test.txt.p7b"); 

        decrypt(E_fileInputStream,E_fileOuputStream,key,"BC");

我认为错误是由我的这部分解密引起的。

 final RecipientInformation recipient = (RecipientInformation)it.next();
            JceKeyTransEnvelopedRecipient ter = new JceKeyTransEnvelopedRecipient((PrivateKey) key);
            final CMSTypedStream recData = recipient.getContentStream(ter);

异常解包密钥：填充错误：解密错误

Exception unwrapping key: bad padding: Decryption error

java

encryption

jks