用Java验证PKCS#7证书

Question

在Java中需要一些加密例程的帮助.

鉴于PKCS#7签名,我想验证它对可信商店包含的所有证书.我假设签名中包含的所有证书都以正确的顺序形成有效的证书路径(或链,无论如何),以便这样做

• 最顶层(#0)是签名证书;
• 下一个(#1)是一个中间证书,用于签署#0;
• 下一个(#2)是另一个中间证书,用于签署#1;
• 等等.

最后一个证书(#N)由CA签名.

这就是我到目前为止所做的事情:

// Exception handling skipped for readability

//byte[] signature = ...
pkcs7 = new PKCS7(signature); // `sun.security.pkcs.PKCS7;`

// *** Checking some PKCS#7 parameters here

X509Certificate prevCert = null; // Previous certificate we've found
X509Certificate[] certs = pkcs7.getCertificates(); // `java.security.cert.X509Certificate`
for (int i = 0; i < certs.length; i++) {
    // *** Checking certificate validity period here

    if (cert != null) {
        // Verify previous certificate in chain against this one
        prevCert.verify(certs[i].getPublicKey());
    }
    prevCert = certs[i];
}

//String keyStorePath = ...
KeyStore keyStore = KeyStore.getInstance("JKS"); // `java.security.KeyStore`
keyStore.load(new FileInputStream(keyStorePath), null);

// Get trusted VeriSign class 1 certificate
Certificate caCert = keyStore.getCertificate("verisignclass1ca"); // `java.security.cert.Certificate`

// Verify last certificate against trusted certificate
cert.verify(caCert.getPublicKey());

所以问题是 - 如何使用像CertPath朋友这样的标准Java类来完成这项工作？我有一种强烈的感觉,我正在重新发明一辆自行车.或者,如果某人有BouncyCastle库的示例,那也没关系.

红利问题:如何针对受信任的商店验证证书,以便自动选择根证书？

Answer 1

自己找到了解决方案.因此,以下是如何针对受信任的存储提取和验证证书链(为了便于阅读而跳过异常处理):

CertificateFactory cf = CertificateFactory.getInstance("X.509");

// Get ContentInfo
//byte[] signature = ... // PKCS#7 signature bytes
InputStream signatureIn = new ByteArrayInputStream(signature);
DERObject obj = new ASN1InputStream(signatureIn).readObject();
ContentInfo contentInfo = ContentInfo.getInstance(obj);

// Extract certificates
SignedData signedData = SignedData.getInstance(contentInfo.getContent());
Enumeration certificates = signedData.getCertificates().getObjects();

// Build certificate path
List certList = new ArrayList();
while (certificates.hasMoreElements()) {
    DERObject certObj = (DERObject) certificates.nextElement();
    InputStream in = new ByteArrayInputStream(certObj.getDEREncoded());
    certList.add(cf.generateCertificate(in));
}
CertPath certPath = cf.generateCertPath(certList);

// Load key store
//String keyStorePath = ...
KeyStore keyStore = KeyStore.getInstance("JKS");
keyStore.load(new FileInputStream(keyStorePath), null);

// Set validation parameters
PKIXParameters params = new PKIXParameters(keyStore);
params.setRevocationEnabled(false); // to avoid exception on empty CRL

// Validate certificate path
CertPathValidator validator = CertPathValidator.getInstance("PKIX");
CertPathValidatorResult result = validator.validate(certPath, params);

validate() 如果验证失败,将抛出异常.

文档:ASN1Set,ContentInfo,SignedData.所有其他外来名称和相关文档都可以在中找到java.security.cert.

此处没有SUN依赖项,只需要BouncyCastle提供程序库.

这个问题(尤其是答案)也可能有所帮助.