如何使用 Java 对 .docx 文件进行数字签名

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.util.Base64;

KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(2048);
KeyPair kp = kpg.genKeyPair();
PublicKey publicKey = kp.getPublic();
PrivateKey privateKey = kp.getPrivate();

byte[] signature = Signature.getInstance("SHA256withRSA").sign(data);

boolean isValidSignature(byte[] signature, byte[] data) {
    PublicKey publicKey = getPublicKey();
    Signature signatureChecker = Signature.getInstance("SHA256withRSA");
    signatureChecker.initVerify(publicKey);
    signatureChecker.update(data);
    return signatureChecker.verify(signature);
}

String data = "Hello, World!";
byte[] signature = generateSignature(data);
String signedData = Base64.getEncoder().encodeToString(signature) + Base64.getEncoder().encodeToString(data);