Go
Go
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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success := false
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
pdf := chilkat.NewPdf()
// Load a PDF that has cryptographic signatures to be validated
success = pdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf")
if success == false {
fmt.Println(pdf.LastErrorText())
pdf.DisposePdf()
return
}
// Each time we verify a signature, information about the signature is written into
// sigInfo (replacing whatever sigInfo previously contained).
sigInfo := chilkat.NewJsonObject()
sigInfo.SetEmitCompact(false)
// Iterate over each signature and validate each.
numSignatures := pdf.NumSignatures()
validated := false
i := 0
for i < numSignatures {
validated = pdf.VerifySignature(i,sigInfo)
fmt.Println("Signature ", i, " validated: ", validated)
fmt.Println(*sigInfo.Emit())
i = i + 1
}
fmt.Println("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 := chilkat.NewJsonObject()
// 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 := chilkat.NewDtObj()
signingTime := chilkat.NewDtObj()
authAttrSigningTimeUtctime := chilkat.NewDtObj()
var intVal int
var strVal *string = new(string)
var issuerCN *string = new(string)
var serial *string = new(string)
var certSerialNumber *string = new(string)
var certIssuerCN *string = new(string)
var certDigestAlgOid *string = new(string)
var certDigestAlgName *string = new(string)
var contentType *string = new(string)
var messageDigest *string = new(string)
var signingAlgOid *string = new(string)
var signingAlgName *string = new(string)
var authAttr1_2_840_113583_1_1_8Der *string = new(string)
var authAttrContentTypeName *string = new(string)
var authAttrContentTypeOid *string = new(string)
var authAttrMessageDigestName *string = new(string)
var authAttrMessageDigestDigest *string = new(string)
var unauthAttrTimestampTokenName *string = new(string)
var unauthAttrTimestampTokenDer *string = new(string)
var unauthAttrTimestampTokenTimestampSignatureVerified bool
var unauthAttrTimestampTokenTstInfoTsaPolicyId *string = new(string)
var unauthAttrTimestampTokenTstInfoMessageImprintHashAlg *string = new(string)
var unauthAttrTimestampTokenTstInfoMessageImprintDigest *string = new(string)
var unauthAttrTimestampTokenTstInfoMessageImprintDigestMatches bool
var unauthAttrTimestampTokenTstInfoSerialNumber *string = new(string)
var j int
var count_j int
var authAttrSigningTimeName *string = new(string)
var authAttrSigningCertificateName *string = new(string)
var authAttrSigningCertificateDer *string = new(string)
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")
for i < count_i {
json.SetI(i)
intVal = json.IntOf("signatureDictionary./ByteRange[i]")
i = i + 1
}
i = 0
count_i = json.SizeOfArray("signatureDictionary./Prop_Build./App./OS")
for i < count_i {
json.SetI(i)
strVal = json.StringOf("signatureDictionary./Prop_Build./App./OS[i]")
i = i + 1
}
i = 0
count_i = json.SizeOfArray("pkcs7.verify.certs")
for i < count_i {
json.SetI(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")
for i < count_i {
json.SetI(i)
strVal = json.StringOf("pkcs7.verify.digestAlgorithms[i]")
i = i + 1
}
i = 0
count_i = json.SizeOfArray("pkcs7.verify.signerInfo")
for i < count_i {
json.SetI(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")
for j < count_j {
json.SetJ(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")
for j < count_j {
json.SetJ(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")
for i < count_i {
json.SetI(i)
issuerCN = json.StringOf("pkcs7.verify.pkcs7.verify.certs[i].issuerCN")
serial = json.StringOf("pkcs7.verify.pkcs7.verify.certs[i].serial")
i = i + 1
}
pdf.DisposePdf()
sigInfo.DisposeJsonObject()
json.DisposeJsonObject()
unauthAttrTimestampTokenTstInfoGenTime.DisposeDtObj()
signingTime.DisposeDtObj()
authAttrSigningTimeUtctime.DisposeDtObj()