使用 CertificateFactory 使用生成的证书 (X509) 获取 public 密钥

Question

我在使用 X509 证书获取 public 密钥时遇到问题。尝试生成证书时出现错误 "signed fields invalid"。请帮忙

用于生成密钥的代码：

public static PublicKey getPublicKey() throws CertificateException,FileNotFoundException {

    InputStream certFileIs = new FileInputStream("E:\TA_Private.pfx");
    CertificateFactory certfactory = CertificateFactory.getInstance("X.509");
    X509Certificate cert = (X509Certificate) certfactory.generateCertificate(certFileIs);
    PublicKey key = cert.getPublicKey();
    return key;
}

控制台输出：

java.security.cert.CertificateParsingException: signed fields invalid
    at sun.security.x509.X509CertImpl.parse(X509CertImpl.java:1768)
    at sun.security.x509.X509CertImpl.<init>(X509CertImpl.java:196)
    at sun.security.provider.X509Factory.engineGenerateCertificate(X509Factory.java:97)
    at java.security.cert.CertificateFactory.generateCertificate(CertificateFactory.java:339)
    at Keygenerator.getPublicKey(Keygenerator.java:45)
    at KeyMain.main(KeyMain.java:20)

Answer 1

文件解析失败。实际上，由于您的文件名为 TA_Private.pfx，这让我觉得这个文件不是 X509 证书而是 PKCS#12 文件（即可以包含密钥和证书的文件，用于交换秘密 material 系统之间）

要读取 PKCS#12 文件，您可以使用 KeyStore class:

public PublicKey loadPKCS#12(String filePath, char[] password) throws Exception {
  InputStream is = null;
  KeyStore ks = KeyStore.getInstance("PKCS12");
  try {
    is = new FileInputStream(filePath);
    ks.load(is, password);
    for (Enumeration<String> e = ks.aliases(); e.hasMoreElements();) {
      String alias = e.nextElement();
      if (ks.isCertificateEntry(alias)) {
        Certificate cert = ks.getCertificate(alias);
        return cert.getPublicKey();
      }
    }
    return null;
  } finally {
    if (is != null) {
      is.close();
    }
  }
}

这是一个非常简单的示例，它提取第一个找到的证书的 public 密钥。但是 PKCS#12 可以包含多个证书。

使用 CertificateFactory 使用生成的证书 (X509) 获取 public 密钥

Getting public key using the generated certificate(X509) using CertificateFactory

java

x509certificate