使用BouncyCastle向CMS签名添加签名/身份验证属性

Question

我想使用BouncyCastle生成一个简单的CMS签名。这代码管用！

  Security.addProvider(new BouncyCastleProvider());
  String password = "123456";
  KeyStore ks = KeyStore.getInstance("PKCS12");
  ks.load(new FileInputStream("c:/cert_123456.p12"), password.toCharArray());
  String alias = (String)ks.aliases().nextElement();
  PrivateKey key = (PrivateKey)ks.getKey(alias, password.toCharArray());
  Certificate[] chain = ks.getCertificateChain(alias);

  CMSSignedDataGenerator generator = new CMSSignedDataGenerator();

  generator.addSigner(key, (X509Certificate)chain[0], CMSSignedDataGenerator.DIGEST_SHA1);
  ArrayList list = new ArrayList();
  for (int i = 0; i < chain.length; i++) {
       list.add(chain[i]);
  }
  CertStore chainStore = CertStore.getInstance("Collection", new CollectionCertStoreParameters(list), "BC");
  generator.addCertificatesAndCRLs(chainStore);
  CMSProcessable content = new CMSProcessableByteArray("test".getBytes());
  CMSSignedData signedData = generator.generate(content, false, "BC");

  byte[] pk = signedData.getEncoded();

但是，如何添加签名属性呢？
我要删除默认签名属性并添加签名策略标识符。

文章非常欢迎。

Answer 1

首先，您似乎使用了Bouncy Castle最新版本中不推荐使用的构造。要添加经过身份验证/签名的属性，必须将它们打包到AttributeTable中，签名属性添加到签名者，如下所示：

ASN1EncodableVector signedAttributes = new ASN1EncodableVector();
signedAttributes.add(new Attribute(CMSAttributes.contentType, new DERSet(new ASN1ObjectIdentifier("1.2.840.113549.1.7.1"))));
signedAttributes.add(new Attribute(CMSAttributes.messageDigest, new DERSet(new DEROctetString(digestBytes))));
signedAttributes.add(new Attribute(CMSAttributes.signingTime, new DERSet(new DERUTCTime(signingDate))));

AttributeTable signedAttributesTable = new AttributeTable(signedAttributes);

然后在addSigner方法之一中使用它。正如我在开头已经提到的，不推荐使用这种方法，并且鼓励您使用生成器和生成器构建器。下面是一个简短的例子：

    /* Construct signed attributes */
    ASN1EncodableVector signedAttributes = new ASN1EncodableVector();
    signedAttributes.add(new Attribute(CMSAttributes.contentType, new DERSet(new ASN1ObjectIdentifier("1.2.840.113549.1.7.1"))));
    signedAttributes.add(new Attribute(CMSAttributes.messageDigest, new DERSet(new DEROctetString(digestBytes))));
    signedAttributes.add(new Attribute(CMSAttributes.signingTime, new DERSet(new DERUTCTime(signingDate))));

    AttributeTable signedAttributesTable = new AttributeTable(signedAttributes);
    signedAttributesTable.toASN1EncodableVector();
    DefaultSignedAttributeTableGenerator signedAttributeGenerator = new DefaultSignedAttributeTableGenerator(signedAttributesTable);

    /* Build the SignerInfo generator builder, that will build the generator... that will generate the SignerInformation... */
    SignerInfoGeneratorBuilder signerInfoBuilder = new SignerInfoGeneratorBuilder(new JcaDigestCalculatorProviderBuilder().setProvider("BC").build());
    signerInfoBuilder.setSignedAttributeGenerator(signedAttributeGenerator);
    CMSSignedDataGenerator generator = new CMSSignedDataGenerator();
    JcaContentSignerBuilder contentSigner = new JcaContentSignerBuilder("SHA1withRSA");
    contentSigner.setProvider("BC");

    generator.addSignerInfoGenerator(signerInfoBuilder.build(contentSigner.build(this.signingKey), new X509CertificateHolder(this.signingCert.getEncoded())));

    ArrayList<X509CertificateHolder> signingChainHolder = new ArrayList<X509CertificateHolder>();
    Iterator i = this.signingChain.iterator();
    while (i.hasNext()) {
        X509CertificateObject cert = (X509CertificateObject)i.next();
        signingChainHolder.add(new X509CertificateHolder(cert.getEncoded()));
    }

    generator.addCertificates(new JcaCertStore(signingChainHolder));
    generator.generate(new CMSAbsentContent(), "BC").getEncoded();

它相当庞大，可能还不能工作（我正在编写它，在研究一些东西时无意中发现了您的问题），特别是签名日期部分，它可能必须是new DERSet（new Time（new Date))（更新：它可以使用derutctime)。

有点偏离主题：我仍然搞不清签名属性和身份验证属性之间的区别，Bouncy Castle有两个DefaultAuthenticatedAttributeTableGenerator和DefaultSignedAttributeTableGenerator类，它们与签名者很好地配合。这两者在signingTime方面似乎有一些小的区别，SignedAttributes在默认情况下添加signingTime（如果不存在）。RFC提到了这两种属性类型，但我找不到任何明确的内容。