Visual FoxPro
Visual FoxPro
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 Visual FoxPro Downloads
LOCAL lnSuccess
LOCAL loPdf
LOCAL loSigInfo
LOCAL lnNumSignatures
LOCAL lnValidated
LOCAL i
LOCAL loJson
LOCAL loUnauthAttrTimestampTokenTstInfoGenTime
LOCAL loSigningTime
LOCAL loAuthAttrSigningTimeUtctime
LOCAL lnIntVal
LOCAL lcStrVal
LOCAL lcIssuerCN
LOCAL lcSerial
LOCAL lcCertSerialNumber
LOCAL lcCertIssuerCN
LOCAL lcCertDigestAlgOid
LOCAL lcCertDigestAlgName
LOCAL lcContentType
LOCAL lcMessageDigest
LOCAL lcSigningAlgOid
LOCAL lcSigningAlgName
LOCAL lcAuthAttr1_2_840_113583_1_1_8Der
LOCAL lcAuthAttrContentTypeName
LOCAL lcAuthAttrContentTypeOid
LOCAL lcAuthAttrMessageDigestName
LOCAL lcAuthAttrMessageDigestDigest
LOCAL lcUnauthAttrTimestampTokenName
LOCAL lcUnauthAttrTimestampTokenDer
LOCAL lnUnauthAttrTimestampTokenTimestampSignatureVerified
LOCAL lcUnauthAttrTimestampTokenTstInfoTsaPolicyId
LOCAL lcUnauthAttrTimestampTokenTstInfoMessageImprintHashAlg
LOCAL lcUnauthAttrTimestampTokenTstInfoMessageImprintDigest
LOCAL lnUnauthAttrTimestampTokenTstInfoMessageImprintDigestMatches
LOCAL lcUnauthAttrTimestampTokenTstInfoSerialNumber
LOCAL j
LOCAL lnCount_j
LOCAL lcAuthAttrSigningTimeName
LOCAL lcAuthAttrSigningCertificateName
LOCAL lcAuthAttrSigningCertificateDer
LOCAL lcSignatureDictionary_Contents
LOCAL lcSignatureDictionary_Filter
LOCAL lcSignatureDictionary_M
LOCAL lcSignatureDictionary_Name
LOCAL lcSignatureDictionary_Prop_Build_App_Name
LOCAL lnSignatureDictionary_Prop_Build_App_R
LOCAL lcSignatureDictionary_Prop_Build_App_REx
LOCAL lnSignatureDictionary_Prop_Build_App_TrustedMode
LOCAL lcSignatureDictionary_Prop_Build_Filter_Date
LOCAL lcSignatureDictionary_Prop_Build_Filter_Name
LOCAL lnSignatureDictionary_Prop_Build_Filter_R
LOCAL lnSignatureDictionary_Prop_Build_Filter_V
LOCAL lcSignatureDictionary_Prop_Build_PubSec_Date
LOCAL lnSignatureDictionary_Prop_Build_PubSec_NonEFontNoWarn
LOCAL lnSignatureDictionary_Prop_Build_PubSec_R
LOCAL lcSignatureDictionary_SubFilter
LOCAL lcSignatureDictionary_Type
LOCAL lnCount_i
lnSuccess = 0
* This example requires the Chilkat API to have been previously unlocked.
* See Global Unlock Sample for sample code.
loPdf = CreateObject('Chilkat.Pdf')
* Load a PDF that has cryptographic signatures to be validated
lnSuccess = loPdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf")
IF (lnSuccess = 0) THEN
? loPdf.LastErrorText
RELEASE loPdf
CANCEL
ENDIF
* Each time we verify a signature, information about the signature is written into
* sigInfo (replacing whatever sigInfo previously contained).
loSigInfo = CreateObject('Chilkat.JsonObject')
loSigInfo.EmitCompact = 0
* Iterate over each signature and validate each.
lnNumSignatures = loPdf.NumSignatures
lnValidated = 0
i = 0
DO WHILE i < lnNumSignatures
lnValidated = loPdf.VerifySignature(i,loSigInfo)
? "Signature " + STR(i) + " validated: " + STR(lnValidated)
? loSigInfo.Emit()
i = i + 1
ENDDO
? "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.
loJson = CreateObject('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
loUnauthAttrTimestampTokenTstInfoGenTime = CreateObject('Chilkat.DtObj')
loSigningTime = CreateObject('Chilkat.DtObj')
loAuthAttrSigningTimeUtctime = CreateObject('Chilkat.DtObj')
lnValidated = loJson.BoolOf("validated")
lcSignatureDictionary_Contents = loJson.StringOf("signatureDictionary./Contents")
lcSignatureDictionary_Filter = loJson.StringOf("signatureDictionary./Filter")
lcSignatureDictionary_M = loJson.StringOf("signatureDictionary./M")
lcSignatureDictionary_Name = loJson.StringOf("signatureDictionary./Name")
lcSignatureDictionary_Prop_Build_App_Name = loJson.StringOf("signatureDictionary./Prop_Build./App./Name")
lnSignatureDictionary_Prop_Build_App_R = loJson.IntOf("signatureDictionary./Prop_Build./App./R")
lcSignatureDictionary_Prop_Build_App_REx = loJson.StringOf("signatureDictionary./Prop_Build./App./REx")
lnSignatureDictionary_Prop_Build_App_TrustedMode = loJson.BoolOf("signatureDictionary./Prop_Build./App./TrustedMode")
lcSignatureDictionary_Prop_Build_Filter_Date = loJson.StringOf("signatureDictionary./Prop_Build./Filter./Date")
lcSignatureDictionary_Prop_Build_Filter_Name = loJson.StringOf("signatureDictionary./Prop_Build./Filter./Name")
lnSignatureDictionary_Prop_Build_Filter_R = loJson.IntOf("signatureDictionary./Prop_Build./Filter./R")
lnSignatureDictionary_Prop_Build_Filter_V = loJson.IntOf("signatureDictionary./Prop_Build./Filter./V")
lcSignatureDictionary_Prop_Build_PubSec_Date = loJson.StringOf("signatureDictionary./Prop_Build./PubSec./Date")
lnSignatureDictionary_Prop_Build_PubSec_NonEFontNoWarn = loJson.BoolOf("signatureDictionary./Prop_Build./PubSec./NonEFontNoWarn")
lnSignatureDictionary_Prop_Build_PubSec_R = loJson.IntOf("signatureDictionary./Prop_Build./PubSec./R")
lcSignatureDictionary_SubFilter = loJson.StringOf("signatureDictionary./SubFilter")
lcSignatureDictionary_Type = loJson.StringOf("signatureDictionary./Type")
i = 0
lnCount_i = loJson.SizeOfArray("signatureDictionary./ByteRange")
DO WHILE i < lnCount_i
loJson.I = i
lnIntVal = loJson.IntOf("signatureDictionary./ByteRange[i]")
i = i + 1
ENDDO
i = 0
lnCount_i = loJson.SizeOfArray("signatureDictionary./Prop_Build./App./OS")
DO WHILE i < lnCount_i
loJson.I = i
lcStrVal = loJson.StringOf("signatureDictionary./Prop_Build./App./OS[i]")
i = i + 1
ENDDO
i = 0
lnCount_i = loJson.SizeOfArray("pkcs7.verify.certs")
DO WHILE i < lnCount_i
loJson.I = i
lcIssuerCN = loJson.StringOf("pkcs7.verify.certs[i].issuerCN")
lcSerial = loJson.StringOf("pkcs7.verify.certs[i].serial")
i = i + 1
ENDDO
i = 0
lnCount_i = loJson.SizeOfArray("pkcs7.verify.digestAlgorithms")
DO WHILE i < lnCount_i
loJson.I = i
lcStrVal = loJson.StringOf("pkcs7.verify.digestAlgorithms[i]")
i = i + 1
ENDDO
i = 0
lnCount_i = loJson.SizeOfArray("pkcs7.verify.signerInfo")
DO WHILE i < lnCount_i
loJson.I = i
lcCertSerialNumber = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.serialNumber")
lcCertIssuerCN = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.issuerCN")
lcCertDigestAlgOid = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid")
lcCertDigestAlgName = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName")
lcContentType = loJson.StringOf("pkcs7.verify.signerInfo[i].contentType")
lcMessageDigest = loJson.StringOf("pkcs7.verify.signerInfo[i].messageDigest")
lcSigningAlgOid = loJson.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid")
lcSigningAlgName = loJson.StringOf("pkcs7.verify.signerInfo[i].signingAlgName")
lcAuthAttr1_2_840_113583_1_1_8Der = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113583.1.1.8".der')
lcAuthAttrContentTypeName = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".name')
lcAuthAttrContentTypeOid = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".oid')
lcAuthAttrMessageDigestName = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".name')
lcAuthAttrMessageDigestDigest = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".digest')
lcUnauthAttrTimestampTokenName = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".name')
lcUnauthAttrTimestampTokenDer = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".der')
lnUnauthAttrTimestampTokenTimestampSignatureVerified = loJson.BoolOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".timestampSignatureVerified')
lcUnauthAttrTimestampTokenTstInfoTsaPolicyId = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.tsaPolicyId')
lcUnauthAttrTimestampTokenTstInfoMessageImprintHashAlg = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.messageImprint.hashAlg')
lcUnauthAttrTimestampTokenTstInfoMessageImprintDigest = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.messageImprint.digest')
lnUnauthAttrTimestampTokenTstInfoMessageImprintDigestMatches = loJson.BoolOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.messageImprint.digestMatches')
lcUnauthAttrTimestampTokenTstInfoSerialNumber = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.serialNumber')
loJson.DtOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.genTime',0,loUnauthAttrTimestampTokenTstInfoGenTime)
j = 0
lnCount_j = loJson.SizeOfArray('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.digestAlgorithms')
DO WHILE j < lnCount_j
loJson.J = j
lcStrVal = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.digestAlgorithms[j]')
j = j + 1
ENDDO
j = 0
lnCount_j = loJson.SizeOfArray('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo')
DO WHILE j < lnCount_j
loJson.J = j
lcCertSerialNumber = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.serialNumber')
lcCertIssuerCN = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.issuerCN')
lcCertDigestAlgOid = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.digestAlgOid')
lcCertDigestAlgName = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.digestAlgName')
lcContentType = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].contentType')
loJson.DtOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].signingTime',0,loSigningTime)
lcMessageDigest = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].messageDigest')
lcSigningAlgOid = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].signingAlgOid')
lcSigningAlgName = loJson.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].signingAlgName')
lcAuthAttrContentTypeName = loJson.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')
lcAuthAttrContentTypeOid = loJson.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')
lcAuthAttrSigningTimeName = loJson.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')
loJson.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',0,loAuthAttrSigningTimeUtctime)
lcAuthAttrSigningCertificateName = loJson.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')
lcAuthAttrSigningCertificateDer = loJson.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')
lcAuthAttrMessageDigestName = loJson.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')
lcAuthAttrMessageDigestDigest = loJson.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
ENDDO
i = i + 1
ENDDO
i = 0
lnCount_i = loJson.SizeOfArray("pkcs7.verify.pkcs7.verify.certs")
DO WHILE i < lnCount_i
loJson.I = i
lcIssuerCN = loJson.StringOf("pkcs7.verify.pkcs7.verify.certs[i].issuerCN")
lcSerial = loJson.StringOf("pkcs7.verify.pkcs7.verify.certs[i].serial")
i = i + 1
ENDDO
RELEASE loPdf
RELEASE loSigInfo
RELEASE loJson
RELEASE loUnauthAttrTimestampTokenTstInfoGenTime
RELEASE loSigningTime
RELEASE loAuthAttrSigningTimeUtctime