使用IText 7向PDF添加数字签名

Question

对于IText 5，添加数字签名相当简单。其文档的链接是：http://developers.itextpdf.com/examples/security/digital-signatures-white-paper/digital-signatures-chapter-2

是否有人可以在ITEXT 7中共享此操作的文档链接？我已经尝试了各种方法，但都没有效果。在线找不到任何链接。我可以取消签名和检查签名，但不能添加它。

Answer 1

数字签名白皮书代码示例到iText 7的移植可以在iText 7 Java signature samples github repository测试源包com.itextpdf.samples.signatures中找到，例如，摘录自简单的C2_01_SignHelloWorld示例：

public void sign(String src, String dest,
                 Certificate[] chain,
                 PrivateKey pk, String digestAlgorithm, String provider,
                 PdfSigner.CryptoStandard subfilter,
                 String reason, String location)
        throws GeneralSecurityException, IOException {
    // Creating the reader and the signer
    PdfReader reader = new PdfReader(src);
    PdfSigner signer = new PdfSigner(reader, new FileOutputStream(dest), false);
    // Creating the appearance
    PdfSignatureAppearance appearance = signer.getSignatureAppearance()
            .setReason(reason)
            .setLocation(location)
            .setReuseAppearance(false);
    Rectangle rect = new Rectangle(36, 648, 200, 100);
    appearance
            .setPageRect(rect)
            .setPageNumber(1);
    signer.setFieldName("sig");
    // Creating the signature
    IExternalSignature pks = new PrivateKeySignature(pk, digestAlgorithm, provider);
    IExternalDigest digest = new BouncyCastleDigest();
    signer.signDetached(digest, pks, chain, null, null, null, 0, subfilter);
}