(Node.js) Validate PDF Signatures

See more PDF Signatures Examples

This example demonstrates how to validate the signatures in a PDF and also shows how to get information from each signature.

Note: This example requires Chilkat v9.5.0.85 or greater.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var pdf = new chilkat.Pdf();

    // Load a PDF that has cryptographic signatures to be validated
    var success = pdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf");
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    // Each time we verify a signature, information about the signature is written into
    // sigInfo (replacing whatever sigInfo previously contained).
    var sigInfo = new chilkat.JsonObject();
    sigInfo.EmitCompact = false;

    // Iterate over each signature and validate each.
    var numSignatures = pdf.NumSignatures;
    var validated = false;
    var i = 0;
    while (i < numSignatures) {
        validated = pdf.VerifySignature(i,sigInfo);
        console.log("Signature " + i + " validated: " + validated);
        console.log(sigInfo.Emit());
        i = i+1;
    }

    console.log("Finished.");

    // When VerifySignature validates a signature, a lot of information is deposited into the JSON sigInfo object.
    // The information can vary depending on what was included in the signature (for example, various authenticated attributes
    // and unauthenticated attributes may or may not be included).
    // Here is a sample of the information you'll see.
    // 
    // The following online tool can be used to generate code to parse any given JSON.
    // Generate Parsing Code from JSON

    // {
    //   "validated": true,
    //   "signatureDictionary": {         <--- This is the contents of the PDF Signature Dictionary for this signature.
    //     "/ByteRange": [
    //       0,
    //       154682,
    //       170512,
    //       3233
    //     ],
    //     "/Contents": "<hex_data>",
    //     "/Filter": "/Adobe.PPKLite",        <--- The meaning of the Signature Dictionary entries are defined in the PDF format specification document.
    //     "/M": "D:20201006110216-05'00'",
    //     "/Name": "yubikey rsa 1024 authentication",
    //     "/Prop_Build": {
    //       "/App": {
    //         "/Name": "/Adobe#20Acrobat#20Pro#20DC",
    //         "/OS": [
    //           "/Win"
    //         ],
    //         "/R": 1313792,
    //         "/REx": "2020.012.20048",
    //         "/TrustedMode": true
    //       },
    //       "/Filter": {
    //         "/Date": "Sep 11 2020 16:30:54",
    //         "/Name": "/Adobe.PPKLite",
    //         "/R": 131104,
    //         "/V": 2
    //       },
    //       "/PubSec": {
    //         "/Date": "Sep 11 2020 16:30:54",
    //         "/NonEFontNoWarn": true,
    //         "/R": 131105
    //       }
    //     },
    //     "/SubFilter": "/adbe.pkcs7.detached",
    //     "/Type": "/Sig"
    //   },
    //   "pkcs7": {          <--- This is the content of the CMS signature.
    //     "verify": {
    //       "certs": [      <--- Each signing certificate is listed here (by issuer common name and signing cert's serail number (in hex))
    //         {
    //           "issuerCN": "yubikey rsa 1024 authentication",
    //           "serial": "66BE58138D761E92BC594A722932657BE26D421F"
    //         }
    //       ],
    //       "digestAlgorithms": [
    //         "sha256"
    //       ],
    //       "signerInfo": [     <--- contains data from each SignerInfo
    //         {
    //           "cert": {
    //             "serialNumber": "66BE58138D761E92BC594A722932657BE26D421F",
    //             "issuerCN": "yubikey rsa 1024 authentication",
    //             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
    //             "digestAlgName": "SHA256"
    //           },
    //           "contentType": "1.2.840.113549.1.7.1",
    //           "messageDigest": "btQOuSEvC31mdRFHtyEUPw8R9NuKfk0XPcQ6Lcmn6pk=",
    //           "signingAlgOid": "1.2.840.113549.1.1.11",
    //           "signingAlgName": "RSA-SHA256-PKCSV-1_5",
    //           "authAttr": {     <--- CMS authenticated attributes are contained here.
    //             "1.2.840.113583.1.1.8": {
    //               "der": "MAA="
    //             },
    //             "1.2.840.113549.1.9.3": {
    //               "name": "contentType",
    //               "oid": "1.2.840.113549.1.7.1"
    //             },
    //             "1.2.840.113549.1.9.4": {
    //               "name": "messageDigest",
    //               "digest": "btQOuSEvC31mdRFHtyEUPw8R9NuKfk0XPcQ6Lcmn6pk="
    //             }
    //           },
    //           "unauthAttr": {    <--- CMS unauthenticated attributes are contained here.
    //             "1.2.840.113549.1.9.16.2.14": {
    //               "name": "timestampToken",
    //               "der": "MIIOvAYJKo ... Es/70g=",
    //               "verify": {
    //                 "digestAlgorithms": [
    //                   "sha256"
    //                 ],
    //                 "signerInfo": [
    //                   {
    //                     "cert": {
    //                       "serialNumber": "04CD3F8568AE76C61BB0FE7160CCA76D",
    //                       "issuerCN": "DigiCert SHA2 Assured ID Timestamping CA",
    //                       "digestAlgOid": "2.16.840.1.101.3.4.2.1",
    //                       "digestAlgName": "SHA256"
    //                     },
    //                     "contentType": "1.2.840.113549.1.9.16.1.4",
    //                     "signingTime": "201006160423Z",
    //                     "messageDigest": "Atv5Rj3kidB8IR6CplYiX3o6De/k8SC6JJ6uUPAGO0g=",
    //                     "signingAlgOid": "1.2.840.113549.1.1.1",
    //                     "signingAlgName": "RSA-PKCSV-1_5",
    //                     "authAttr": {
    //                       "1.2.840.113549.1.9.3": {
    //                         "name": "contentType",
    //                         "oid": "1.2.840.113549.1.9.16.1.4"
    //                       },
    //                       "1.2.840.113549.1.9.5": {
    //                         "name": "signingTime",
    //                         "utctime": "201006160423Z"
    //                       },
    //                       "1.2.840.113549.1.9.16.2.12": {
    //                         "name": "signingCertificate",
    //                         "der": "MBowGDAWBBQDJb1QXtqWMC3CL0+gHkwovig0xQ=="
    //                       },
    //                       "1.2.840.113549.1.9.4": {
    //                         "name": "messageDigest",
    //                         "digest": "Atv5Rj3kidB8IR6CplYiX3o6De/k8SC6JJ6uUPAGO0g="
    //                       }
    //                     }
    //                   }
    //                 ]
    //               },
    //               "timestampSignatureVerified": true,
    //               "tstInfo": {
    //                 "tsaPolicyId": "2.16.840.1.114412.7.1",
    //                 "messageImprint": {
    //                   "hashAlg": "sha256",
    //                   "digest": "gLJtrRWUSDfjzDkF1MfWG1wyHA6FrUJLkWMGRG+eMlA=",
    //                   "digestMatches": true
    //                 },
    //                 "serialNumber": "00CE57E1113970607EF63B1D1160545321",
    //                 "genTime": "20201006160423Z"
    //               }
    //             }
    //           }
    //         }
    //       ],
    //       "pkcs7": {
    //         "verify": {
    //           "certs": [
    //             {
    //               "issuerCN": "DigiCert SHA2 Assured ID Timestamping CA",
    //               "serial": "04CD3F8568AE76C61BB0FE7160CCA76D"
    //             },
    //             {
    //               "issuerCN": "DigiCert Assured ID Root CA",
    //               "serial": "0AA125D6D6321B7E41E405DA3697C215"
    //             }
    //           ]
    //         }
    //       }
    //     }
    //   }
    // }

    // **** The point of this code is to show how to get at each desired piece of information contained in the signature.
    // **** If your signature contains additional information not shown here, then you can use the online tool to generate the parse code.
    // **** It is likely you're only interested in a few items of information, and therefore you wouldn't copy all of this code, but might
    // **** choose to use bits and pieces to get the information you find important.

    var json = new chilkat.JsonObject();

    // Imagine that the "json" object contains the information obtained by validating a signature...
    // The code below was generated using the online tool:  Generate Parsing Code from JSON

    var unauthAttrTimestampTokenTstInfoGenTime = new chilkat.DtObj();
    var signingTime = new chilkat.DtObj();
    var authAttrSigningTimeUtctime = new chilkat.DtObj();
    var intVal;
    var strVal;
    var issuerCN;
    var serial;
    var certSerialNumber;
    var certIssuerCN;
    var certDigestAlgOid;
    var certDigestAlgName;
    var contentType;
    var messageDigest;
    var signingAlgOid;
    var signingAlgName;
    var authAttr1_2_840_113583_1_1_8Der;
    var authAttrContentTypeName;
    var authAttrContentTypeOid;
    var authAttrMessageDigestName;
    var authAttrMessageDigestDigest;
    var unauthAttrTimestampTokenName;
    var unauthAttrTimestampTokenDer;
    var unauthAttrTimestampTokenTimestampSignatureVerified;
    var unauthAttrTimestampTokenTstInfoTsaPolicyId;
    var unauthAttrTimestampTokenTstInfoMessageImprintHashAlg;
    var unauthAttrTimestampTokenTstInfoMessageImprintDigest;
    var unauthAttrTimestampTokenTstInfoMessageImprintDigestMatches;
    var unauthAttrTimestampTokenTstInfoSerialNumber;
    var j;
    var count_j;
    var authAttrSigningTimeName;
    var authAttrSigningCertificateName;
    var authAttrSigningCertificateDer;

    validated = json.BoolOf("validated");
    var signatureDictionary_Contents = json.StringOf("signatureDictionary./Contents");
    var signatureDictionary_Filter = json.StringOf("signatureDictionary./Filter");
    var signatureDictionary_M = json.StringOf("signatureDictionary./M");
    var signatureDictionary_Name = json.StringOf("signatureDictionary./Name");
    var signatureDictionary_Prop_Build_App_Name = json.StringOf("signatureDictionary./Prop_Build./App./Name");
    var signatureDictionary_Prop_Build_App_R = json.IntOf("signatureDictionary./Prop_Build./App./R");
    var signatureDictionary_Prop_Build_App_REx = json.StringOf("signatureDictionary./Prop_Build./App./REx");
    var signatureDictionary_Prop_Build_App_TrustedMode = json.BoolOf("signatureDictionary./Prop_Build./App./TrustedMode");
    var signatureDictionary_Prop_Build_Filter_Date = json.StringOf("signatureDictionary./Prop_Build./Filter./Date");
    var signatureDictionary_Prop_Build_Filter_Name = json.StringOf("signatureDictionary./Prop_Build./Filter./Name");
    var signatureDictionary_Prop_Build_Filter_R = json.IntOf("signatureDictionary./Prop_Build./Filter./R");
    var signatureDictionary_Prop_Build_Filter_V = json.IntOf("signatureDictionary./Prop_Build./Filter./V");
    var signatureDictionary_Prop_Build_PubSec_Date = json.StringOf("signatureDictionary./Prop_Build./PubSec./Date");
    var signatureDictionary_Prop_Build_PubSec_NonEFontNoWarn = json.BoolOf("signatureDictionary./Prop_Build./PubSec./NonEFontNoWarn");
    var signatureDictionary_Prop_Build_PubSec_R = json.IntOf("signatureDictionary./Prop_Build./PubSec./R");
    var signatureDictionary_SubFilter = json.StringOf("signatureDictionary./SubFilter");
    var signatureDictionary_Type = json.StringOf("signatureDictionary./Type");
    i = 0;
    var count_i = json.SizeOfArray("signatureDictionary./ByteRange");
    while (i < count_i) {
        json.I = i;
        intVal = json.IntOf("signatureDictionary./ByteRange[i]");
        i = i+1;
    }

    i = 0;
    count_i = json.SizeOfArray("signatureDictionary./Prop_Build./App./OS");
    while (i < count_i) {
        json.I = i;
        strVal = json.StringOf("signatureDictionary./Prop_Build./App./OS[i]");
        i = i+1;
    }

    i = 0;
    count_i = json.SizeOfArray("pkcs7.verify.certs");
    while (i < count_i) {
        json.I = i;
        issuerCN = json.StringOf("pkcs7.verify.certs[i].issuerCN");
        serial = json.StringOf("pkcs7.verify.certs[i].serial");
        i = i+1;
    }

    i = 0;
    count_i = json.SizeOfArray("pkcs7.verify.digestAlgorithms");
    while (i < count_i) {
        json.I = i;
        strVal = json.StringOf("pkcs7.verify.digestAlgorithms[i]");
        i = i+1;
    }

    i = 0;
    count_i = json.SizeOfArray("pkcs7.verify.signerInfo");
    while (i < count_i) {
        json.I = i;
        certSerialNumber = json.StringOf("pkcs7.verify.signerInfo[i].cert.serialNumber");
        certIssuerCN = json.StringOf("pkcs7.verify.signerInfo[i].cert.issuerCN");
        certDigestAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid");
        certDigestAlgName = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName");
        contentType = json.StringOf("pkcs7.verify.signerInfo[i].contentType");
        messageDigest = json.StringOf("pkcs7.verify.signerInfo[i].messageDigest");
        signingAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid");
        signingAlgName = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgName");
        authAttr1_2_840_113583_1_1_8Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113583.1.1.8\".der");
        authAttrContentTypeName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".name");
        authAttrContentTypeOid = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".oid");
        authAttrMessageDigestName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".name");
        authAttrMessageDigestDigest = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".digest");
        unauthAttrTimestampTokenName = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".name");
        unauthAttrTimestampTokenDer = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".der");
        unauthAttrTimestampTokenTimestampSignatureVerified = json.BoolOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".timestampSignatureVerified");
        unauthAttrTimestampTokenTstInfoTsaPolicyId = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.tsaPolicyId");
        unauthAttrTimestampTokenTstInfoMessageImprintHashAlg = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.messageImprint.hashAlg");
        unauthAttrTimestampTokenTstInfoMessageImprintDigest = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.messageImprint.digest");
        unauthAttrTimestampTokenTstInfoMessageImprintDigestMatches = json.BoolOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.messageImprint.digestMatches");
        unauthAttrTimestampTokenTstInfoSerialNumber = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.serialNumber");
        json.DtOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.genTime",false,unauthAttrTimestampTokenTstInfoGenTime);
        j = 0;
        count_j = json.SizeOfArray("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.digestAlgorithms");
        while (j < count_j) {
            json.J = j;
            strVal = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.digestAlgorithms[j]");
            j = j+1;
        }

        j = 0;
        count_j = json.SizeOfArray("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo");
        while (j < count_j) {
            json.J = j;
            certSerialNumber = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.serialNumber");
            certIssuerCN = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.issuerCN");
            certDigestAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.digestAlgOid");
            certDigestAlgName = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.digestAlgName");
            contentType = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].contentType");
            json.DtOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].signingTime",false,signingTime);
            messageDigest = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].messageDigest");
            signingAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].signingAlgOid");
            signingAlgName = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].signingAlgName");
            authAttrContentTypeName = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.3\".name");
            authAttrContentTypeOid = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.3\".oid");
            authAttrSigningTimeName = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.5\".name");
            json.DtOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.5\".utctime",false,authAttrSigningTimeUtctime);
            authAttrSigningCertificateName = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.16.2.12\".name");
            authAttrSigningCertificateDer = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.16.2.12\".der");
            authAttrMessageDigestName = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.4\".name");
            authAttrMessageDigestDigest = json.StringOf("pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].authAttr.\"1.2.840.113549.1.9.4\".digest");
            j = j+1;
        }

        i = i+1;
    }

    i = 0;
    count_i = json.SizeOfArray("pkcs7.verify.pkcs7.verify.certs");
    while (i < count_i) {
        json.I = i;
        issuerCN = json.StringOf("pkcs7.verify.pkcs7.verify.certs[i].issuerCN");
        serial = json.StringOf("pkcs7.verify.pkcs7.verify.certs[i].serial");
        i = i+1;
    }


}

chilkatExample();