使用Java将外部PKCS1字节数组和证书添加到CMS容器

2019-11-22 01:03:34 阅读：330 来源： 互联网

标签：digital-signature pkcs7 bouncycastle java

我们拥有创建PKCS1 v2.1数字签名的客户端应用程序(Applets和Silverlight).由于未将原始内容下载到客户端,因此将数字签名创建为PKCS1,因此仅将内容的哈希发送到客户端以节省带宽.

我们正在尝试创建PKCS7 / CMS容器服务器端based on the information from this post：

>阅读证书并以X509证书类型加载
>将PKCS1签名读取为base64并作为字节数组加载
>实例化新的ASN1ObjectIdentifier并设置PKCS1 OID(1.2.840.113549.1.1)
>使用asn1对象和signare字节[]作为参数创建新的CMSTypedData CMSProcessableByteArray
>创建新的CMSSignedGenerator并添加证书
>使用CMSTypedData类型创建新的CMSSignedData作为分离的签名

但是,转到第5步和第6步时,事情就会中断,因为BC CMSSignedGenerator和CMSSignedData类不支持添加没有私钥的签署者：

CMS创建：

    // Add BC to environment
    Security.addProvider(new BouncyCastleProvider());

    // Read certificate and convert to X509Certificate
    CertificateFactory certFactory = CertificateFactory.getInstance("X.509");
    Path certPath = Paths.get("C:\\MyCertificate.cer");
    byte[] certData = Files.readAllBytes(certPath);
    InputStream in = new ByteArrayInputStream(certData);
    X509Certificate cert = (X509Certificate)certFactory.generateCertificate(in);

    // Add signer certificates to List and add them to store
    List<X509Certificate> certList = new ArrayList<X509Certificate>();
    certList.add(cert);
    Store certs = new JcaCertStore(certList);

    // Get signature in Base64, decode and convert to byte array
    // Signature signature = Signature.getInstance("SHA1WithRSA", "BC");
    String signatureBase64 = "gjTbsD0vSOi6nMlRVbpTLRQ5j+g2h8iEH1DgQx93PDBuwzWT47urKxMAS+75dAhQrkreLt9TGZaDN85e5xEpIF12mK1G+AgCNc370I1bjxOvUU67IVxHkZ+IX8kzSiD2uNuQtk3IrwUqyL30TIo+LDAXmY1AQVZwXAaOYG4bXxI=";
    BASE64Decoder decoder = new BASE64Decoder();
    byte[] signatureByte = decoder.decodeBuffer(signatureBase64);

    // Instantiate new ANS1ObjectIdentifier to identify PKCS1 signature
    ASN1ObjectIdentifier asn1OidPkcs1 = new ASN1ObjectIdentifier("1.2.840.113549.1.1");

    // Table generator
    /*AttributeTable attrT = new AttributeTable();
    SimpleAttributeTableGenerator sAttrTGen = new SimpleAttributeTableGenerator();*/

    // Instantiate new CMSProcessable object
    CMSTypedData msg = new CMSProcessableByteArray(asn1OidPkcs1, signatureByte);

    // Instantiate new CMSSignedDataGenerator object
    CMSSignedDataGenerator gen = new CMSSignedDataGenerator();

    // ContentSigner sha1Signer = new JcaContentSignerBuilder("SHA1withRSA").setProvider("BC").s
    gen.addCertificates(certs);
    CMSSignedData sigData = gen.generate(msg, false);


    // BASE64Encoder encoder = new BASE64Encoder();
    new File("C:\\MyCMS.p7s");
    FileOutputStream fileOuputStream = new FileOutputStream("C:\\Users\\gregwerner\\Documents\\Archivos\\miFirma.p7s"); 
    fileOuputStream.write(sigData.getEncoded());
    fileOuputStream.flush();
    fileOuputStream.close();

}

关于如何完成CMS容器的任何想法？也许使用AttributeTable为时间戳等添加了多个OID,但这似乎也不起作用.

解决方法:

在查看此参考项目https://code.google.com/p/j4ops/之后,我找到了答案.尽管该指南特别针对使用iText的PDF(使用加密操作的BC：http://itextpdf.com/book/digitalsignatures20130304.pdf)处理PDF,但它也是一个很大的帮助.窍门是将签名操作委托给外部提供程序(PKCS11 ,PKCS12等),例如,通过实现使用sign(byte [] toEncrypt)方法的Signer接口.这样,可以设置提供程序,然后仅调用sign方法,并保留有关如何对提供程序本身进行签名的实现详细信息.

Bouncy Castle使用CMSSignedDataGenerator类和SignerInf内部类来分别构建CMS容器和签名者信息.因此,诀窍是建立一个不需要私钥的SignerInf对象,因为sign()操作应委托给提供者.私钥甚至可能不可用,特别是在使用智能卡时.此外,在签名哈希和构建CMS容器时,需要考虑需要添加为签名属性和/或未签名属性的信息.因此,这些是解决问题的基本步骤：

// Build the items to encrypt, objects for method parameters would be obtained previously.
byte[] toEncrypt = externalSignerInfoGenerator.getCmsBytesToSign(hash, 
            signingTime, 
            PKCSObjectIdentifiers.data, 
            x509Cert, 
            timeStampToken, 
            ocsp);
// The externalSignerInfoGenerator.getCmsBytesToSign is a method from a re implemention of the 
// SignerInf inner class from CMSSignedDataGenerator and is used to get a byte array from an 
// org.bouncycastle.asn1.ASN1EncodableVector. To build the vector one should add attributes to
// their corresponding OID's using the org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers interface,
// for example:
ASN1EncodableVector signedAttrVector = buildSignedAttributes (hash, signingTime, contentType,
x509Cert, ocspResp);
// This would call the buildSignedAttributes method to build the signed attributes vector
ASN1EncodableVector signedAttrVector = new ASN1EncodableVector();
// Add CMS attributes
signedAttrVector.add (new Attribute(CMSAttributes.contentType, new DERSet (contentType)));
signedAttrVector.add (new Attribute (CMSAttributes.signingTime, new DERSet(new Time (signingTime))));
signedAttrVector.add(new Attribute(CMSAttributes.messageDigest, new DERSet(new DEROctetString(hash))));
// Not all attributes are considered in BC's CMSAttributes interface, therefore one would have to add 
// an additional step:
signedAttrVector.add(buildOcspResponseAttribute(ocspResp));
// This method would call buildOcspResponseAttribute to add the object as a PKCSObjectIdentifier
protected Attribute buildOcspResponseAttribute (byte[] ocspResp) throws IOException, CMSException {
    return new Attribute (PKCSObjectIdentifiers.id_aa_ets_revocationRefs, 
    new DERSet(DERUtil.readDERObject(ocspResp)));
}  

// Call sign method from provider, such as PKCS11, PKCS12, etc.
byte [] signature = getSignProvider().sign(toEncrypt);
// Now build standard org.bouncycastle.cms.SignerInfoGenerator with hash, signed data 
// and certificate to add to CMS, create attached or detached signature
// create signed envelope
CMSSignedData envdata = externalCMSSignedDataGenerator.generate(false);                
byte[] enveloped = envdata.getEncoded();

标签：digital-signature,pkcs7,bouncycastle,java
来源： https://codeday.me/bug/20191122/2055969.html

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使用Java将外部PKCS1字节数组和证书添加到CMS容器