如何使用数字签名页面签署PDF文档？

Question

我正在尝试以数字方式签署文档页面。它在逻辑上是否正确？ 目前签名只有一页，有什么我做错了吗？

PdfReader reader = new PdfReader(src);

FileOutputStream os = new FileOutputStream(dest);

PdfStamper stamper = PdfStamper.createSignature(reader, os, '\0');

// Creating the appearance

PdfSignatureAppearance appearance = stamper.getSignatureAppearance();

appearance.setLocation(location);
        appearance.setCertificationLevel(PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED);

appearance.setVisibleSignature(new Rectangle(44, 170, 144, 221), 1, "sig");

appearance.setVisibleSignature(new Rectangle(44, 170, 144, 221), 7, "sig");

// Creating the signature

ExternalSignature pks = new PrivateKeySignature(pk, digestAlgorithm, provider);

ExternalDigest digest = new BouncyCastleDigest();

MakeSignature.signDetached(appearance, digest, pks, chain, crlList,ocspClient, tsaClient, estimatedSize,subfilter);