(Go) 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.

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

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

    mime := chilkat.NewMime()

    // Load the signed MIME from a file...
    success := mime.LoadMimeFile("qa_data/mime/detached_sig.eml")
    if success == false {
        fmt.Println(mime.LastErrorText())
        mime.DisposeMime()
        return
    }

    // Verify the S/MIME and restore the MIME
    // to the structure/content it had prior to signing.
    verified := mime.Verify()
    if verified == false {
        fmt.Println(mime.LastErrorText())
        mime.DisposeMime()
        return
    }

    // Examine the details of what was verified.
    json := mime.LastJsonData()
    json.SetEmitCompact(false)
    fmt.Println(*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 := chilkat.NewDtObj()
    authAttrSigningTimeUtctime := chilkat.NewDtObj()
    var issuerCN *string = new(string)
    var serial *string = new(string)
    var strVal *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 authAttrContentTypeName *string = new(string)
    var authAttrContentTypeOid *string = new(string)
    var authAttrSigningTimeName *string = new(string)
    var authAttrMessageDigestName *string = new(string)
    var authAttrMessageDigestDigest *string = new(string)
    var authAttr1_2_840_113549_1_9_15Der *string = new(string)
    var authAttr1_3_6_1_4_1_311_16_4Der *string = new(string)

    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")
        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
    }

    json.DisposeJsonObject()

    mime.DisposeMime()
    signingTime.DisposeDtObj()
    authAttrSigningTimeUtctime.DisposeDtObj()