如何使用 Java 对 .docx 文件进行数字签名

Question

如何使用 java 对 .docx 文件进行数字签名，签名应嵌入到 .docx 文件中。我使用了 Apache-poi API，但无法对 .docx 文件进行数字签名。需要哪个 API 以及如何使用？

Answer 1

虽然这个问题很老，但我想创建参考答案以链接到。我不久前修改了e-Id applet 代码，现在可以进行签名了。

查看POIs documentation了解更多详情。

基本代码如下：

// loading the keystore - pkcs12 is used here, but of course jks & co are also valid
// the keystore needs to contain a private key and it's certificate having a
// 'digitalSignature' key usage
char password[] = "test".toCharArray();
File file = new File("test.pfx");
KeyStore keystore = KeyStore.getInstance("PKCS12");
FileInputStream fis = new FileInputStream(file);
keystore.load(fis, password);
fis.close();

// extracting private key and certificate
String alias = "xyz"; // alias of the keystore entry
Key key = keystore.getKey(alias, password);
X509Certificate x509 = (X509Certificate)keystore.getCertificate(alias);

// filling the SignatureConfig entries (minimum fields, more options are available ...)
SignatureConfig signatureConfig = new SignatureConfig();
signatureConfig.setKey(keyPair.getPrivate());
signatureConfig.setSigningCertificateChain(Collections.singletonList(x509));
OPCPackage pkg = OPCPackage.open(..., PackageAccess.READ_WRITE);
signatureConfig.setOpcPackage(pkg);

// adding the signature document to the package
SignatureInfo si = new SignatureInfo();
si.setSignatureConfig(signatureConfig);
si.confirmSignature();
// optionally verify the generated signature
boolean b = si.verifySignature();
assert (b);
// write the changes back to disc
pkg.close();