java pdf 签名 修改,使用Java中的自定义数字签名来签名PDF
时间: 2024-03-10 09:45:09 浏览: 75
要使用Java中的自定义数字签名来签名PDF,可以使用Bouncy Castle库。
以下是实现数字签名的步骤:
1. 导入Bouncy Castle库
```
import org.bouncycastle.jce.provider.BouncyCastleProvider;
```
2. 注册Bouncy Castle库
```
Security.addProvider(new BouncyCastleProvider());
```
3. 读取PDF文件
```
FileInputStream fis = new FileInputStream("example.pdf");
PdfReader reader = new PdfReader(fis);
FileOutputStream fos = new FileOutputStream("signed.pdf");
PdfStamper stamper = PdfStamper.createSignature(reader, fos, '\0');
```
4. 创建数字签名
```
PrivateKey privateKey = // 获取私钥
Certificate[] chain = // 获取证书链
PdfSignatureAppearance appearance = stamper.getSignatureAppearance();
appearance.setCrypto(null, chain, null, PdfSignatureAppearance.WINCER_SIGNED);
```
5. 设置签名位置
```
appearance.setVisibleSignature(new Rectangle(100, 100, 200, 200), 1, null);
```
6. 签名PDF文件
```
ExternalSignature signature = new PrivateKeySignature(privateKey, "SHA-256", "BC");
ExternalDigest digest = new BouncyCastleDigest();
MakeSignature.signDetached(appearance, digest, signature, chain, null, null, null, 0, MakeSignature.CryptoStandard.CMS);
```
7. 关闭文件流
```
stamper.close();
reader.close();
fis.close();
fos.close();
```
这样就可以使用Java中的自定义数字签名来签名PDF了。