在 JAVA 中使用 PKCS #7 对数据进行签名

Question

我想签署一个文本文件（将来可能是.exe 文件或其他文件） 使用 PKCS#7 并使用 Java 验证签名。

1. 我需要知道什么？
2. 在哪里可以找到 API（.jar 和文档）？
3. 我需要执行哪些步骤才能签署数据并验证数据？

如果可能，请提供代码 sn-p。

Answer 1

我认为您需要以下 2 个 Bouncy Castle 罐子来生成 PKCS7 数字签名：

• bcprov-jdk15on-147.jar（适用于 JDK 1.5 - JDK 1.7）

• bcmail-jdk15on-147.jar（适用于 JDK 1.5 - JDK 1.7）

您可以从here 下载 Bouncy Castle 罐子。

您需要使用公钥和私钥对设置您的密钥库。 您只需要生成数字签名的私钥和验证它的公钥。

以下是您对 pkcs7 内容进行签名的方式（为简洁起见，省略了异常处理）：

import java.io.FileInputStream;
import java.io.InputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.Security;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.List;
import org.bouncycastle.cert.jcajce.JcaCertStore;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.CMSSignedDataGenerator;
import org.bouncycastle.cms.CMSTypedData;
import org.bouncycastle.cms.jcajce.JcaSignerInfoGeneratorBuilder;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.operator.ContentSigner;
import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
import org.bouncycastle.operator.jcajce.JcaDigestCalculatorProviderBuilder;
import org.bouncycastle.util.Store;
import org.bouncycastle.util.encoders.Base64;

public final class PKCS7Signer {

    private static final String PATH_TO_KEYSTORE = "/path/to/keyStore";
    private static final String KEY_ALIAS_IN_KEYSTORE = "My_Private_Key";
    private static final String KEYSTORE_PASSWORD = "MyPassword";
    private static final String SIGNATUREALGO = "SHA1withRSA";

    public PKCS7Signer() {
    }

    KeyStore loadKeyStore() throws Exception {

        KeyStore keystore = KeyStore.getInstance("JKS");
        InputStream is = new FileInputStream(PATH_TO_KEYSTORE);
        keystore.load(is, KEYSTORE_PASSWORD.toCharArray());
        return keystore;
    }

    CMSSignedDataGenerator setUpProvider(final KeyStore keystore) throws Exception {

        Security.addProvider(new BouncyCastleProvider());

        Certificate[] certchain = (Certificate[]) keystore.getCertificateChain(KEY_ALIAS_IN_KEYSTORE);

        final List<Certificate> certlist = new ArrayList<Certificate>();

        for (int i = 0, length = certchain == null ? 0 : certchain.length; i < length; i++) {
            certlist.add(certchain[i]);
        }

        Store certstore = new JcaCertStore(certlist);

        Certificate cert = keystore.getCertificate(KEY_ALIAS_IN_KEYSTORE);

        ContentSigner signer = new JcaContentSignerBuilder(SIGNATUREALGO).setProvider("BC").
                build((PrivateKey) (keystore.getKey(KEY_ALIAS_IN_KEYSTORE, KEYSTORE_PASSWORD.toCharArray())));

        CMSSignedDataGenerator generator = new CMSSignedDataGenerator();

        generator.addSignerInfoGenerator(new JcaSignerInfoGeneratorBuilder(new JcaDigestCalculatorProviderBuilder().setProvider("BC").
                build()).build(signer, (X509Certificate) cert));

        generator.addCertificates(certstore);

        return generator;
    }

    byte[] signPkcs7(final byte[] content, final CMSSignedDataGenerator generator) throws Exception {

        CMSTypedData cmsdata = new CMSProcessableByteArray(content);
        CMSSignedData signeddata = generator.generate(cmsdata, true);
        return signeddata.getEncoded();
    }

    public static void main(String[] args) throws Exception {

        PKCS7Signer signer = new PKCS7Signer();
        KeyStore keyStore = signer.loadKeyStore();
        CMSSignedDataGenerator signatureGenerator = signer.setUpProvider(keyStore);
        String content = "some bytes to be signed";
        byte[] signedBytes = signer.signPkcs7(content.getBytes("UTF-8"), signatureGenerator);
        System.out.println("Signed Encoded Bytes: " + new String(Base64.encode(signedBytes)));
    }
}

Answer 2

PKCS#7 现在称为 CMS（加密消息语法），您将需要 Bouncy Castle PKIX 库来创建一个。它有充足的文档和完善的邮件列表。

我不会提供代码 sn-p，这违反了家规。先自己试试吧。