(Go) Verify a .p7m and get Algorithm Information

Demonstrates how to verify a .p7m and then examine the algorithms used by 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()

    inFile := "qa_data/p7m/brainpoolP256r1.p7m"
    outFile := "qa_output/something.dat"

    // Verify and extract the signed data.
    success := crypt.VerifyP7M(inFile,outFile)
    if success == false {
        fmt.Println(crypt.LastErrorText())
        crypt.DisposeCrypt2()
        return
    }

    // Examine details about the signature(s)
    json := crypt.LastJsonData()
    json.SetEmitCompact(false)
    fmt.Println(*json.Emit())

    // Sample output

    // {
    //   "pkcs7": {
    //     "verify": {
    //       "digestAlgorithms": [
    //         "sha256"
    //       ],
    //       "signerInfo": [
    //         {
    //           "cert": {
    //             "serialNumber": "FFFFE552B302FFFFFF1E34C3ACEB2FFFF",
    //             "issuerCN": "The common name of the cert...",
    //             "issuerDN": "",
    //             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
    //             "digestAlgName": "SHA256"
    //           },
    //           "contentType": "1.2.840.113549.1.7.1",
    //           "signingTime": "190409140500Z",
    //           "messageDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
    //           "signingAlgOid": "1.2.840.10045.4.3.2",
    //           "signerDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
    //           "authAttr": [
    //             {
    //               "oid": "1.2.840.113549.1.9.3",
    //               "oidName": "contentType"
    //             },
    //             {
    //               "oid": "1.2.840.113549.1.9.5",
    //               "oidName": "signingTime"
    //             },
    //             {
    //               "oid": "1.2.840.113549.1.9.52",
    //               "oidName": "1.2.840.113549.1.9.52",
    //               "der": "MBs ... AwI="
    //             },
    //             {
    //               "oid": "1.2.840.113549.1.9.4",
    //               "oidName": "messageDigest"
    //             },
    //             {
    //               "oid": "1.2.840.113549.1.9.16.2.47",
    //               "oidName": "signingCertificateV2",
    //               "der": "MCYw .. 7PlQ=="
    //             },
    //             {
    //               "oid": "1.2.840.113549.1.9.20",
    //               "oidName": "1.2.840.113549.1.9.20"
    //             }
    //           ]
    //         }
    //       ]
    //     }
    //   }
    // }

    // Code for parsing the above JSON...
    var i int
    var count_i int
    var strVal *string = new(string)
    var certSerialNumber *string = new(string)
    var certIssuerCN *string = new(string)
    var certIssuerDN *string = new(string)
    var certDigestAlgOid *string = new(string)
    var certDigestAlgName *string = new(string)
    var contentType *string = new(string)
    var signingTime *string = new(string)
    var messageDigest *string = new(string)
    var signingAlgOid *string = new(string)
    var signerDigest *string = new(string)
    var j int
    var count_j int
    var oid *string = new(string)
    var oidName *string = new(string)
    var der *string = new(string)

    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")
        certIssuerDN = json.StringOf("pkcs7.verify.signerInfo[i].cert.issuerDN")
        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")
        signingTime = json.StringOf("pkcs7.verify.signerInfo[i].signingTime")
        messageDigest = json.StringOf("pkcs7.verify.signerInfo[i].messageDigest")
        signingAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid")
        signerDigest = json.StringOf("pkcs7.verify.signerInfo[i].signerDigest")
        j = 0
        count_j = json.SizeOfArray("pkcs7.verify.signerInfo[i].authAttr")
        for j < count_j {
            json.SetJ(j)
            oid = json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].oid")
            oidName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].oidName")
            der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].der")
            j = j + 1
        }

        i = i + 1
    }

    json.DisposeJsonObject()

    fmt.Println("Success!")

    crypt.DisposeCrypt2()