pkijs
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Public Key Infrastructure (PKI) is the basis of how identity and key management is performed on the web today. PKIjs is a pure JavaScript library implementing the formats that are used in PKI applications. It is built on WebCrypto and aspires to make it p
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HTML
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>PDF signature checking</title>
<script type="text/javascript" src="org/pkijs/common.js"></script>
<script type="text/javascript" src="org/pkijs/asn1.js"></script>
<script type="text/javascript" src="org/pkijs/x509_schema.js"></script>
<script type="text/javascript" src="org/pkijs/x509_simpl.js"></script>
<script type="text/javascript" src="org/pkijs/cms_schema.js"></script>
<script type="text/javascript" src="org/pkijs/cms_simpl.js"></script>
<script type="text/javascript" src="pdfjs/pdf.js"></script>
<style type="text/css">
body{background:#EFEFEF;font:normal 14px/16px Helvetica, Arial, sans-serif;}
.wrapper{
width:600px;
margin:50px auto;
padding:50px;
border:solid 2px #CCC;
border-radius:10px;
-webkit-border-radius:10px;
box-shadow:0 0 12px 3px #CDCDCD;
-webkit-box-shadow:0 0 12px 3px #CDCDCD;
background:#FFF;
}
label{
font:bold 16px/20px Helvetica, Arial, sans-serif;
margin:0 0 8px;
}
textarea{
width:500px;
border:solid 1px #999;
border-radius:5px;
-webkit-border-radius:5px;
height:340px;
font:normal 12px/15px monospace;
display:block;
margin:0 0 12px;
box-shadow:0 0 5px 5px #EFEFEF inset;
-webkit-box-shadow:0 0 5px 5px #EFEFEF inset;
padding:20px;
resize: none;
}
a{
display:inline-block;
padding:5px 15px;
background:#ACD0EC;
border:solid 1px #4C6181;
color:#000;
font:normal 14px/16px Helvetica, Arial, sans-serif;
}
a:hover{
background:#DAEBF8;
cursor:pointer;
}
.header-block {
margin-top:30px;
font:bold 16px/20px Helvetica, Arial, sans-serif;
}
.border-block{
border:solid 2px #999;
border-radius:5px;
-webkit-border-radius:5px;
margin:10px 0 0;
padding:20px 30px;
background:#F0F4FF;
}
.border-block h2{
margin:0 0 16px;
font:bold 22px/24px Helvetica, Arial, sans-serif;
}
.border-block p{
margin:0 0 12px;
}
.border-block p .type{
font-weight:bold;
display:inline-block;
width:176px;
}
.border-block .two-col{
overflow:hidden;
margin:0 0 16px;
}
.border-block .two-col .subject{
width:180px;
font-weight:bold;
margin:0 0 12px;
float:left;
}
.border-block .two-col #cms-signed-attributes{
margin:0;
padding:0;
float:left;
list-style:none;
}
.border-block .two-col #cms-signed-attributes li p{
margin:0;
}
.border-block .two-col #cms-signed-attributes li p span{
width:40px;
display:inline-block;
margin:0 0 5px;
}
.border-block .two-col #cms-signed-exten{
overflow:hidden;
padding:0 0 0 17px;
margin:0;
list-style-type:square;
}
table {
border:solid;
border-collapse:collapse;
border-color:black;
}
th {
text-align:center;
background: #ccc;
padding: 5px;
border: 1px solid black;
}
td {
padding: 5px;
border: 1px solid black;
}
</style>
<script>
//*********************************************************************************
var trustedCertificates = new Array(); // Array of org.pkijs.simpl.CERT
//*********************************************************************************
function verifyPDFSignature(buffer)
{
try
{
var view = new Uint8Array(buffer);
var pdf = new PDFDocument(null, view, null);
pdf.parseStartXRef();
pdf.parse();
var acroForm = pdf.xref.root.get("AcroForm");
if(typeof acroForm === "undefined")
throw new Error("The PDF has no signature!");
var fields = acroForm.get("Fields");
if(isRef(fields[0]) === false)
throw new Error("Wrong structure of PDF!");
var sigField = pdf.xref.fetch(fields[0]);
var sigFieldType = sigField.get("FT");
if((typeof sigFieldType === "undefined") || (sigFieldType.name !== "Sig"))
throw new Error("Wrong structure of PDF!");
var v = sigField.get("V");
var byteRange = v.get("ByteRange");
var contents = v.get("Contents");
var contentLength = contents.length;
var contentBuffer = new ArrayBuffer(contentLength);
var contentView = new Uint8Array(contentBuffer);
for(var i = 0; i < contentLength; i++)
contentView[i] = contents.charCodeAt(i);
var sequence = Promise.resolve();
var asn1 = org.pkijs.fromBER(contentBuffer);
var cms_content_simp = new org.pkijs.simpl.CMS_CONTENT_INFO({ schema: asn1.result });
var cms_signed_simp = new org.pkijs.simpl.CMS_SIGNED_DATA({ schema: cms_content_simp.content });
var signedDataBuffer = new ArrayBuffer(byteRange[1] + byteRange[3]);
var signedDataView = new Uint8Array(signedDataBuffer);
var count = 0;
for(var i = byteRange[0]; i < (byteRange[0] + byteRange[1]); i++, count++)
signedDataView[count] = view[i];
for(var j = byteRange[2]; j < (byteRange[2] + byteRange[3]); j++, count++)
signedDataView[count] = view[j];
sequence = sequence.then(
function()
{
return cms_signed_simp.verify({ signer: 0, data: signedDataBuffer, trusted_certs: trustedCertificates });
}
);
if("signedAttrs" in cms_signed_simp.signerInfos[0])
{
var crypto = org.pkijs.getCrypto();
if(typeof crypto == "undefined")
throw new Error("WebCrypto extension is not installed");
var sha_algorithm = "";
switch(cms_signed_simp.signerInfos[0].digestAlgorithm.algorithm_id)
{
case "1.3.14.3.2.26":
sha_algorithm = "sha-1";
break;
case "2.16.840.1.101.3.4.2.1":
sha_algorithm = "sha-256";
break;
case "2.16.840.1.101.3.4.2.2":
sha_algorithm = "sha-384";
break;
case "2.16.840.1.101.3.4.2.3":
sha_algorithm = "sha-512";
break;
default:
throw new Error("Unknown hashing algorithm");
};
sequence = sequence.then(
function(result)
{
if(result === false)
return new Promise(function(resolve, reject) { reject("Signature verification failed"); });
return crypto.digest({ name: sha_algorithm }, new Uint8Array(signedDataBuffer));
},
function(error)
{
return new Promise(function(resolve, reject) { reject("Error during signature verification"); });
}
);
sequence = sequence.then(
function(result)
{
var messageDigest = new ArrayBuffer(0);
for(var j = 0; j < cms_signed_simp.signerInfos[0].signedAttrs.attributes.length; j++)
{
if(cms_signed_simp.signerInfos[0].signedAttrs.attributes[j].attrType === "1.2.840.113549.1.9.4")
{
messageDigest = cms_signed_simp.signerInfos[0].signedAttrs.attributes[j].attrValues[0].value_block.value_hex;
break;
}
}
if(messageDigest.byteLength === 0)
return new Promise(function(resolve, reject) { reject("No signed attribute \"MessageDigest\""); });
var view1 = new Uint8Array(messageDigest);
var view2 = new Uint8Array(result);
if(view1.length !== view2.length)
return new Promise(function(resolve, reject) { reject("Hash is not correct"); });
for(var i = 0; i < view1.length; i++)
{
if(view1[i] !== view2[i])
return new Promise(function(resolve, reject) { reject("Hash is not correct"); });
}
},
function(error)
{
return new Promise(function(resolve, reject) { reject("Error during hashing data"); });
}
);
}
sequence.then(
function(result)
{
if(typeof result !== "undefined")
{
if(result === false)
{
alert("PDF verification failed!")
return;
}
}
alert("PDF successfully verified!")
},
function(error)
{
alert("Error: " + error);
}
);
}
catch(err)
{
alert(err);
}
}
//*********************************************************************************
function parseCABundle(buffer)
{
// #region Initial variables
var base64Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
var startChars = "-----BEGIN CERTIFICATE-----";
var endChars = "-----END CERTIFICATE-----";
var endLineChars = "\r\n";
var view = new Uint8Array(buffer);
var waitForStart = false;
var middleStage = true;
var waitForEnd = false;
var waitForEndLine = false;
var started = false;
var certBodyEncoded = "";
// #endregion
for(var i = 0; i < view.length; i++)
{
if(started === true)
{
if(base64Chars.indexOf(String.fromCharCode(view[i])) !== (-1))
certBodyEncoded = certBodyEncoded + String.fromCharCode(view[i]);
else
{
if(String.fromCharCode(view[i]) === '-')
{
// #region Decoded trustedCertificates
var asn1 = org.pkijs.fromBER(stringToArrayBuffer(window.atob(certBodyEncoded)));
try
{
trustedCertificates.push(new org.pkijs.simpl.CERT({ schema: asn1.result }));
}
catch(ex)
{
//alert("Wrong certificate format");
//return;
}
// #endregion
// #region Set all "flag variables"
certBodyEncoded = "";
started = false;
waitForEnd = true;
// #endregion
}
}
}
else
{
if(waitForEndLine === true)
{
if(endLineChars.indexOf(String.fromCharCode(view[i])) === (-1))
{
waitForEndLine = false;
if(waitForEnd === true)
{
waitForEnd = false;
middleStage = true;
}
else
{
if(waitForStart === true)
{
waitForStart = false;
started = true;
certBodyEncoded = certBodyEncoded + String.fromCharCode(view[i]);
}
else
middleStage = true;
}
}
}
else
{
if(middleStage === true)
{
if(String.fromCharCode(view[i]) === "-")
{
if((i === 0) ||
((String.fromCharCode(view[i - 1]) === "\r") ||
(String.fromCharCode(view[i - 1]) === "\n")))
{
middleStage = false;
waitForStart = true;
}
}
}
else
{
if(waitForStart === true)
{
if(startChars.indexOf(String.fromCharCode(view[i])) === (-1))
waitForEndLine = true;
}
else
{
if(waitForEnd === true)
{
if(endChars.indexOf(String.fromCharCode(view[i])) === (-1))
waitForEndLine = true;
}
}
}
}
}
}
}
//*********************************************************************************
function handleFileBrowse(evt)
{
var temp_reader = new FileReader();
var current_files = evt.target.files;
temp_reader.onload =
function(event)
{
verifyPDFSignature(event.target.result);
};
temp_reader.readAsArrayBuffer(current_files[0]);
}
//*********************************************************************************
function handleCABundle(evt)
{
var temp_reader = new FileReader();
var current_files = evt.target.files;
temp_reader.onload =
function(event)
{
parseCABundle(event.target.result);
};
temp_reader.readAsArrayBuffer(current_files[0]);
}
//*********************************************************************************
</script>
</head>
<body>
<div id="cert_div" class="wrapper">
<p>
<label for="ca_bundle">Select CA bundle file:</label>
<input type="file" id="ca_bundle" title="Trusted certs" />
</p>
<p>
<label for="pdf_file">Select PDF file:</label>
<input type="file" id="pdf_file" title="PDF to check" />
</p>
</div>
<script>
document.getElementById('pdf_file').addEventListener('change', handleFileBrowse, false);
document.getElementById('ca_bundle').addEventListener('change', handleCABundle, false);
</script>
</body>
</html>