主页 / coding / 问题 / 78820602
Accepted
superkuzet
Asked: 2024-08-01 19:05:47 +0800 CST

使用旧版 iText-2.1.7 将符号添加到 PDF

  • 772

我正在开发一个使用旧版 iText-2.1.7 库的遗留项目。我才刚刚开始弄清楚，而且我暂时不会升级到更新的版本，所以我需要有关此版本的帮助。我需要将签名添加到 pdf，这是我的代码：

def postProcessPdf(pdf: Array[Byte], os: OutputStream): Unit = {
 val reader = new PdfReader(pdf)
 Security.addProvider(new KalkanProvider)
 val stamper = PdfStamper.createSignature(reader, os, '\u0000')
 val appearance = stamper.getSignatureAppearance
 val signDate = Calendar.getInstance
 val pdfSignature = new PdfSignature(PdfName.ADOBE_PPKLITE, PdfName.ADBE_PKCS7_DETACHED)
 pdfSignature.setDate(new PdfDate(signDate))
 pdfSignature.setCert(CryptUtils.cert.getEncoded)
 appearance.setCryptoDictionary(pdfSignature)
 appearance.setCrypto(null, CryptUtils.chain, null, PdfSignatureAppearance.WINCER_SIGNED)
 appearance.setCertificationLevel(PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED)
 val estimatedSize = 8192
 val exc = new HashMap[PdfName, Int]()
 exc.put(PdfName.CONTENTS, estimatedSize * 2 + 2)
 appearance.preClose(exc)
 val data = appearance.getRangeStream()
 val sgn = new PdfPKCS7(null, CryptUtils.chain, null, "SHA256", null, false)
 val digest = MessageDigest.getInstance("SHA256","KALKAN")
 val dataBytes = IOUtils.toByteArray(data)
 digest.update(dataBytes)
 val appeareanceHash = digest.digest()
 val hashToSign = sgn.getAuthenticatedAttributeBytes(appeareanceHash, appearance.getSignDate(), null)
 val signature = Signature.getInstance("SHA256withRSA","KALKAN")
 signature.initSign(CryptUtils.privateKey)
 signature.update(hashToSign)
 val signedHash = signature.sign()
 sgn.setExternalDigest(signedHash,null,"RSA")
 val encodedPKCS7 = sgn.getEncodedPKCS7(signedHash, appearance.getSignDate())
 val paddedSig = new Array[Byte](estimatedSize)
 System.arraycopy(encodedPKCS7, 0, paddedSig, 0, encodedPKCS7.length)
 val dic = new PdfDictionary()
 dic.put(PdfName.CONTENTS, new PdfString(paddedSig).setHexWriting(true))
 appearance.close(dic)
}

Adobe Acrobat Reader 中的结果： 图像 错误：文档自签名以来已被更改或损坏。这是什么意思？我该怎么办？提前谢谢您。PDF 文件：链接

pdf

1 个回答

  1. Best Answer

    您必须对sgn.getAuthenticatedAttributeBytes和sgn.getEncodedPKCS7调用的匹配参数使用相同的参数值。

    在您的代码中您有：

    val hashToSign = sgn.getAuthenticatedAttributeBytes(appeareanceHash, appearance.getSignDate(), null)
...
sgn.setExternalDigest(signedHash,null,"RSA")
val encodedPKCS7 = sgn.getEncodedPKCS7(signedHash, appearance.getSignDate())

    但它应该是

    val hashToSign = sgn.getAuthenticatedAttributeBytes(appeareanceHash, appearance.getSignDate(), null)
...
sgn.setExternalDigest(signedHash,null,"RSA")
val encodedPKCS7 = sgn.getEncodedPKCS7(appeareanceHash, appearance.getSignDate())
    • 0

相关问题