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Ruby

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 Ruby Downloads

Ruby
require 'chilkat'

success = false

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

pdf = Chilkat::CkPdf.new()

# Load a PDF that has cryptographic signatures to be validated
success = pdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

# Each time we verify a signature, information about the signature is written into
# sigInfo (replacing whatever sigInfo previously contained).
sigInfo = Chilkat::CkJsonObject.new()
sigInfo.put_EmitCompact(false)

# Iterate over each signature and validate each.
numSignatures = pdf.get_NumSignatures()
validated = false
i = 0
while i < numSignatures
    validated = pdf.VerifySignature(i,sigInfo)
    print "Signature " + i.to_s() + " validated: " + validated.to_s() + "\n";
    print sigInfo.emit() + "\n";
    i = i + 1
end

print "Finished." + "\n";

# 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::CkJsonObject.new()

# 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::CkDtObj.new()
signingTime = Chilkat::CkDtObj.new()
authAttrSigningTimeUtctime = Chilkat::CkDtObj.new()

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 < count_i
    json.put_I(i)
    intVal = json.IntOf("signatureDictionary./ByteRange[i]")
    i = i + 1
end
i = 0
count_i = json.SizeOfArray("signatureDictionary./Prop_Build./App./OS")
while i < count_i
    json.put_I(i)
    strVal = json.stringOf("signatureDictionary./Prop_Build./App./OS[i]")
    i = i + 1
end
i = 0
count_i = json.SizeOfArray("pkcs7.verify.certs")
while i < count_i
    json.put_I(i)
    issuerCN = json.stringOf("pkcs7.verify.certs[i].issuerCN")
    serial = json.stringOf("pkcs7.verify.certs[i].serial")
    i = i + 1
end
i = 0
count_i = json.SizeOfArray("pkcs7.verify.digestAlgorithms")
while i < count_i
    json.put_I(i)
    strVal = json.stringOf("pkcs7.verify.digestAlgorithms[i]")
    i = i + 1
end
i = 0
count_i = json.SizeOfArray("pkcs7.verify.signerInfo")
while i < count_i
    json.put_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.put_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
    end
    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.put_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
    end
    i = i + 1
end
i = 0
count_i = json.SizeOfArray("pkcs7.verify.pkcs7.verify.certs")
while i < count_i
    json.put_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
end