(Go) Verify a CAdES-BES Signature and Examine Signature Contents

Demonstrates how to validate a .p7m (.p7s) signature and examine the contents of the signature.

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.

    crypt := chilkat.NewCrypt2()

    outputFile := "qa_output/original.xml"
    inFile := "qa_data/p7m/fattura_signature.xml.p7m"

    // Verify the signature and extract the contained file, which in this case is XML.
    success := crypt.VerifyP7M(inFile,outputFile)
    if success == false {
        fmt.Println(crypt.LastErrorText())
        crypt.DisposeCrypt2()
        return
    }

    fmt.Println("Signature validated.")

    // Now let's examine the information about the signature.
    json := crypt.LastJsonData()
    if crypt.LastMethodSuccess() == false {
        // This should never be the case...
        fmt.Println("No information available.")
        crypt.DisposeCrypt2()
        return
    }

    json.SetEmitCompact(false)
    fmt.Println(*json.Emit())

    // Here's an example of the information about the signature:
    // {
    //   "pkcs7": {
    //     "verify": {
    //       "certs": [
    //         {
    //           "issuerCN": "Xyz EU Qualified Certificates CA G1",
    //           "serial": "99A28A51AC389999"
    //         }
    //       ],
    //       "useConstructedOctets": true,
    //       "digestAlgorithms": [
    //         "sha256"
    //       ],
    //       "signerInfo": [
    //         {
    //           "cert": {
    //             "subjectKeyIdentifier": "5VM4x8AWnXf07yzbXuLtbb0U3yY=",
    //             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
    //             "digestAlgName": "SHA256"
    //           },
    //           "signingAlgOid": "1.2.840.113549.1.1.11",
    //           "signingAlgName": "RSA-SHA256-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": "190901152340Z"
    //             },
    //             "1.2.840.113549.1.9.4": {
    //               "name": "messageDigest",
    //               "digest": "y+gd/zAQK33A//HInhaZba7w1fUJleV9AHbP1Ntx6U0="
    //             },
    //             "1.2.840.113549.1.9.16.2.47": {
    //               "name": "signingCertificateV2",
    //               "der": "MIH4MI..w4vv0="
    //             }
    //           }
    //         }
    //       ]
    //     }
    //   }
    // }

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

    authAttrSigningTimeUtctime := chilkat.NewDtObj()
    var issuerCN *string = new(string)
    var serial *string = new(string)
    var strVal *string = new(string)
    var certSubjectKeyIdentifier *string = new(string)
    var certDigestAlgOid *string = new(string)
    var certDigestAlgName *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 authAttrSigningCertificateV2Name *string = new(string)
    var authAttrSigningCertificateV2Der *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)
        certSubjectKeyIdentifier = json.StringOf("pkcs7.verify.signerInfo[i].cert.subjectKeyIdentifier")
        certDigestAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid")
        certDigestAlgName = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName")
        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")
        authAttrSigningCertificateV2Name = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.16.2.47\".name")
        authAttrSigningCertificateV2Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.16.2.47\".der")
        i = i + 1
    }

    json.DisposeJsonObject()

    crypt.DisposeCrypt2()
    authAttrSigningTimeUtctime.DisposeDtObj()