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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.
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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"
$success = $false
# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.
$pdf = New-Object Chilkat.Pdf
# Load a PDF that has cryptographic signatures to be validated
$success = $pdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf")
if ($success -eq $false) {
$($pdf.LastErrorText)
exit
}
# Each time we verify a signature, information about the signature is written into
# sigInfo (replacing whatever sigInfo previously contained).
$sigInfo = New-Object Chilkat.JsonObject
$sigInfo.EmitCompact = $false
# Iterate over each signature and validate each.
$numSignatures = $pdf.NumSignatures
$validated = $false
$i = 0
while ($i -lt $numSignatures) {
$validated = $pdf.VerifySignature($i,$sigInfo)
$("Signature " + $i + " validated: " + $validated)
$($sigInfo.Emit())
$i = $i + 1
}
$("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.
$json = New-Object 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
$unauthAttrTimestampTokenTstInfoGenTime = New-Object Chilkat.DtObj
$signingTime = New-Object Chilkat.DtObj
$authAttrSigningTimeUtctime = New-Object Chilkat.DtObj
$validated = $json.BoolOf("validated")
$signatureDictionary_Contents = $json.StringOf("signatureDictionary./Contents")
$signatureDictionary_Filter = $json.StringOf("signatureDictionary./Filter")
$signatureDictionary_M = $json.StringOf("signatureDictionary./M")
$signatureDictionary_Name = $json.StringOf("signatureDictionary./Name")
$signatureDictionary_Prop_Build_App_Name = $json.StringOf("signatureDictionary./Prop_Build./App./Name")
$signatureDictionary_Prop_Build_App_R = $json.IntOf("signatureDictionary./Prop_Build./App./R")
$signatureDictionary_Prop_Build_App_REx = $json.StringOf("signatureDictionary./Prop_Build./App./REx")
$signatureDictionary_Prop_Build_App_TrustedMode = $json.BoolOf("signatureDictionary./Prop_Build./App./TrustedMode")
$signatureDictionary_Prop_Build_Filter_Date = $json.StringOf("signatureDictionary./Prop_Build./Filter./Date")
$signatureDictionary_Prop_Build_Filter_Name = $json.StringOf("signatureDictionary./Prop_Build./Filter./Name")
$signatureDictionary_Prop_Build_Filter_R = $json.IntOf("signatureDictionary./Prop_Build./Filter./R")
$signatureDictionary_Prop_Build_Filter_V = $json.IntOf("signatureDictionary./Prop_Build./Filter./V")
$signatureDictionary_Prop_Build_PubSec_Date = $json.StringOf("signatureDictionary./Prop_Build./PubSec./Date")
$signatureDictionary_Prop_Build_PubSec_NonEFontNoWarn = $json.BoolOf("signatureDictionary./Prop_Build./PubSec./NonEFontNoWarn")
$signatureDictionary_Prop_Build_PubSec_R = $json.IntOf("signatureDictionary./Prop_Build./PubSec./R")
$signatureDictionary_SubFilter = $json.StringOf("signatureDictionary./SubFilter")
$signatureDictionary_Type = $json.StringOf("signatureDictionary./Type")
$i = 0
$count_i = $json.SizeOfArray("signatureDictionary./ByteRange")
while ($i -lt $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 -lt $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 -lt $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 -lt $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 -lt $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 -lt $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 -lt $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 -lt $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
}