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Swift

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.

Chilkat Swift Downloads

Swift

func chilkatTest() {
    var success: Bool = false

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

    let pdf = CkoPdf()!

    // Load a PDF that has cryptographic signatures to be validated
    success = pdf.loadFile(filePath: "qa_data/pdf/sign_testing_1/helloSigned2.pdf")
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    // Each time we verify a signature, information about the signature is written into
    // sigInfo (replacing whatever sigInfo previously contained).
    let sigInfo = CkoJsonObject()!
    sigInfo.emitCompact = false

    // Iterate over each signature and validate each.
    var numSignatures: Int = pdf.numSignatures.intValue
    var validated: Bool = false
    var i: Int = 0
    while i < numSignatures {
        validated = pdf.verifySignature(index: i, sigInfo: sigInfo)
        print("Signature \(i) validated: \(validated)")
        print("\(sigInfo.emit()!)")
        i = i + 1
    }

    print("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.

    let json = CkoJsonObject()!

    // 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

    let unauthAttrTimestampTokenTstInfoGenTime = CkoDtObj()!
    let signingTime = CkoDtObj()!
    let authAttrSigningTimeUtctime = CkoDtObj()!
    var intVal: Int
    var strVal: String?
    var issuerCN: String?
    var serial: String?
    var certSerialNumber: String?
    var certIssuerCN: String?
    var certDigestAlgOid: String?
    var certDigestAlgName: String?
    var contentType: String?
    var messageDigest: String?
    var signingAlgOid: String?
    var signingAlgName: String?
    var authAttr1_2_840_113583_1_1_8Der: String?
    var authAttrContentTypeName: String?
    var authAttrContentTypeOid: String?
    var authAttrMessageDigestName: String?
    var authAttrMessageDigestDigest: String?
    var unauthAttrTimestampTokenName: String?
    var unauthAttrTimestampTokenDer: String?
    var unauthAttrTimestampTokenTimestampSignatureVerified: Bool
    var unauthAttrTimestampTokenTstInfoTsaPolicyId: String?
    var unauthAttrTimestampTokenTstInfoMessageImprintHashAlg: String?
    var unauthAttrTimestampTokenTstInfoMessageImprintDigest: String?
    var unauthAttrTimestampTokenTstInfoMessageImprintDigestMatches: Bool
    var unauthAttrTimestampTokenTstInfoSerialNumber: String?
    var j: Int
    var count_j: Int
    var authAttrSigningTimeName: String?
    var authAttrSigningCertificateName: String?
    var authAttrSigningCertificateDer: String?

    validated = json.bool(of: "validated")
    var signatureDictionary_Contents: String? = json.string(of: "signatureDictionary./Contents")
    var signatureDictionary_Filter: String? = json.string(of: "signatureDictionary./Filter")
    var signatureDictionary_M: String? = json.string(of: "signatureDictionary./M")
    var signatureDictionary_Name: String? = json.string(of: "signatureDictionary./Name")
    var signatureDictionary_Prop_Build_App_Name: String? = json.string(of: "signatureDictionary./Prop_Build./App./Name")
    var signatureDictionary_Prop_Build_App_R: Int = json.int(of: "signatureDictionary./Prop_Build./App./R").intValue
    var signatureDictionary_Prop_Build_App_REx: String? = json.string(of: "signatureDictionary./Prop_Build./App./REx")
    var signatureDictionary_Prop_Build_App_TrustedMode: Bool = json.bool(of: "signatureDictionary./Prop_Build./App./TrustedMode")
    var signatureDictionary_Prop_Build_Filter_Date: String? = json.string(of: "signatureDictionary./Prop_Build./Filter./Date")
    var signatureDictionary_Prop_Build_Filter_Name: String? = json.string(of: "signatureDictionary./Prop_Build./Filter./Name")
    var signatureDictionary_Prop_Build_Filter_R: Int = json.int(of: "signatureDictionary./Prop_Build./Filter./R").intValue
    var signatureDictionary_Prop_Build_Filter_V: Int = json.int(of: "signatureDictionary./Prop_Build./Filter./V").intValue
    var signatureDictionary_Prop_Build_PubSec_Date: String? = json.string(of: "signatureDictionary./Prop_Build./PubSec./Date")
    var signatureDictionary_Prop_Build_PubSec_NonEFontNoWarn: Bool = json.bool(of: "signatureDictionary./Prop_Build./PubSec./NonEFontNoWarn")
    var signatureDictionary_Prop_Build_PubSec_R: Int = json.int(of: "signatureDictionary./Prop_Build./PubSec./R").intValue
    var signatureDictionary_SubFilter: String? = json.string(of: "signatureDictionary./SubFilter")
    var signatureDictionary_Type: String? = json.string(of: "signatureDictionary./Type")
    i = 0
    var count_i: Int = json.size(ofArray: "signatureDictionary./ByteRange").intValue
    while i < count_i {
        json.i = i
        intVal = json.int(of: "signatureDictionary./ByteRange[i]").intValue
        i = i + 1
    }

    i = 0
    count_i = json.size(ofArray: "signatureDictionary./Prop_Build./App./OS").intValue
    while i < count_i {
        json.i = i
        strVal = json.string(of: "signatureDictionary./Prop_Build./App./OS[i]")
        i = i + 1
    }

    i = 0
    count_i = json.size(ofArray: "pkcs7.verify.certs").intValue
    while i < count_i {
        json.i = i
        issuerCN = json.string(of: "pkcs7.verify.certs[i].issuerCN")
        serial = json.string(of: "pkcs7.verify.certs[i].serial")
        i = i + 1
    }

    i = 0
    count_i = json.size(ofArray: "pkcs7.verify.digestAlgorithms").intValue
    while i < count_i {
        json.i = i
        strVal = json.string(of: "pkcs7.verify.digestAlgorithms[i]")
        i = i + 1
    }

    i = 0
    count_i = json.size(ofArray: "pkcs7.verify.signerInfo").intValue
    while i < count_i {
        json.i = i
        certSerialNumber = json.string(of: "pkcs7.verify.signerInfo[i].cert.serialNumber")
        certIssuerCN = json.string(of: "pkcs7.verify.signerInfo[i].cert.issuerCN")
        certDigestAlgOid = json.string(of: "pkcs7.verify.signerInfo[i].cert.digestAlgOid")
        certDigestAlgName = json.string(of: "pkcs7.verify.signerInfo[i].cert.digestAlgName")
        contentType = json.string(of: "pkcs7.verify.signerInfo[i].contentType")
        messageDigest = json.string(of: "pkcs7.verify.signerInfo[i].messageDigest")
        signingAlgOid = json.string(of: "pkcs7.verify.signerInfo[i].signingAlgOid")
        signingAlgName = json.string(of: "pkcs7.verify.signerInfo[i].signingAlgName")
        authAttr1_2_840_113583_1_1_8Der = json.string(of: "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113583.1.1.8\".der")
        authAttrContentTypeName = json.string(of: "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".name")
        authAttrContentTypeOid = json.string(of: "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".oid")
        authAttrMessageDigestName = json.string(of: "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".name")
        authAttrMessageDigestDigest = json.string(of: "pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".digest")
        unauthAttrTimestampTokenName = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".name")
        unauthAttrTimestampTokenDer = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".der")
        unauthAttrTimestampTokenTimestampSignatureVerified = json.bool(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".timestampSignatureVerified")
        unauthAttrTimestampTokenTstInfoTsaPolicyId = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.tsaPolicyId")
        unauthAttrTimestampTokenTstInfoMessageImprintHashAlg = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.messageImprint.hashAlg")
        unauthAttrTimestampTokenTstInfoMessageImprintDigest = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.messageImprint.digest")
        unauthAttrTimestampTokenTstInfoMessageImprintDigestMatches = json.bool(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.messageImprint.digestMatches")
        unauthAttrTimestampTokenTstInfoSerialNumber = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.serialNumber")
        json.dt(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".tstInfo.genTime", bLocal: false, dt: unauthAttrTimestampTokenTstInfoGenTime)
        j = 0
        count_j = json.size(ofArray: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.digestAlgorithms").intValue
        while j < count_j {
            json.j = j
            strVal = json.string(of: "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.size(ofArray: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo").intValue
        while j < count_j {
            json.j = j
            certSerialNumber = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.serialNumber")
            certIssuerCN = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.issuerCN")
            certDigestAlgOid = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.digestAlgOid")
            certDigestAlgName = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].cert.digestAlgName")
            contentType = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].contentType")
            json.dt(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].signingTime", bLocal: false, dt: signingTime)
            messageDigest = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].messageDigest")
            signingAlgOid = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].signingAlgOid")
            signingAlgName = json.string(of: "pkcs7.verify.signerInfo[i].unauthAttr.\"1.2.840.113549.1.9.16.2.14\".verify.signerInfo[j].signingAlgName")
            authAttrContentTypeName = json.string(of: "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.string(of: "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.string(of: "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.dt(of: "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", bLocal: false, dt: authAttrSigningTimeUtctime)
            authAttrSigningCertificateName = json.string(of: "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.string(of: "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.string(of: "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.string(of: "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.size(ofArray: "pkcs7.verify.pkcs7.verify.certs").intValue
    while i < count_i {
        json.i = i
        issuerCN = json.string(of: "pkcs7.verify.pkcs7.verify.certs[i].issuerCN")
        serial = json.string(of: "pkcs7.verify.pkcs7.verify.certs[i].serial")
        i = i + 1
    }


}