(Chilkat2-Python) Verify and Unwrap S/MIME, and get Information about CMS Signature

Demonstrates calling the Verify method to verify and unwrap S/MIME. The MIME is restored to the original structure that it would have originally had prior to signing. The Verify method works with both detached signatures, as well as opaque/attached signatures.

Calls LastJsonData to get information about the signature(s) that were verified.

Chilkat2 Python Downloads install with pip pip3 install chilkat2 or download... Python Module for Windows, Linux, Alpine Linux, MacOS, Solaris

import sys
import chilkat2

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

mime = chilkat2.Mime()

# Load the signed MIME from a file...
success = mime.LoadMimeFile("qa_data/mime/detached_sig.eml")
if (success == False):
    print(mime.LastErrorText)
    sys.exit()

# Verify the S/MIME and restore the MIME
# to the structure/content it had prior to signing.
verified = mime.Verify()
if (verified == False):
    print(mime.LastErrorText)
    sys.exit()

# Examine the details of what was verified.
# json is a CkJsonObject
json = mime.LastJsonData()
json.EmitCompact = False
print(json.Emit())

# The code to parse the following JSON (i.e. extract desired information) is shown below..

# {
#   "pkcs7": {
#     "verify": {
#       "certs": [
#         {
#           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
#           "serial": "0702A21A85B84B659E180A6EE6F5A365"
#         },
#         {
#           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
#           "serial": "008B5B75568454850B00CFAF3848CEB1A4"
#         },
#         {
#           "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
#           "serial": "619C55C32FF6BD1A7B7E0330D21C8F3C"
#         }
#       ],
#       "digestAlgorithms": [
#         "sha1"
#       ],
#       "signerInfo": [
#         {
#           "cert": {
#             "serialNumber": "619C55C32FF6BD1A7B7E0330D21C8F3C",
#             "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
#             "digestAlgOid": "1.3.14.3.2.26",
#             "digestAlgName": "SHA1"
#           },
#           "contentType": "1.2.840.113549.1.7.1",
#           "signingTime": "160428055000Z",
#           "messageDigest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY=",
#           "signingAlgOid": "1.2.840.113549.1.1.1",
#           "signingAlgName": "RSA-PKCSV-1_5",
#           "authAttr": {
#             "1.2.840.113549.1.9.3": {
#               "name": "contentType",
#               "oid": "1.2.840.113549.1.7.1"
#             },
#             "1.2.840.113549.1.9.5": {
#               "name": "signingTime",
#               "utctime": "160428055000Z"
#             },
#             "1.2.840.113549.1.9.4": {
#               "name": "messageDigest",
#               "digest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY="
#             },
#             "1.2.840.113549.1.9.15": {
#               "der": "MFAwCwYJYIZIAWUDBAECMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIAgDANBggqhkiG9w0DAgIBQDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKA=="
#             },
#             "1.3.6.1.4.1.311.16.4": {
#               "der": "MIG7MIG...7fgMw0hyPPA=="
#             }
#           }
#         }
#       ]
#     }
#   }
# }

# Use this online tool to generate parsing code from sample JSON: 
# Generate Parsing Code from JSON

signingTime = chilkat2.DtObj()
authAttrSigningTimeUtctime = chilkat2.DtObj()

i = 0
count_i = json.SizeOfArray("pkcs7.verify.certs")
while i < 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 < 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 < 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")
    json.DtOf("pkcs7.verify.signerInfo[i].signingTime",False,signingTime)
    messageDigest = json.StringOf("pkcs7.verify.signerInfo[i].messageDigest")
    signingAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid")
    signingAlgName = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgName")
    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")
    authAttrSigningTimeName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".name")
    json.DtOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".utctime",False,authAttrSigningTimeUtctime)
    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")
    authAttr1_2_840_113549_1_9_15Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.15\".der")
    authAttr1_3_6_1_4_1_311_16_4Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.3.6.1.4.1.311.16.4\".der")
    i = i + 1