(VB.NET) Sign Mexico Pedimento

Add a signature to a Mexico pedimento file.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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

Dim success As Boolean

' This is the contents before signing:

' 500|1|3621|4199800|400||
' 601|3621|4199800|400|IN|1||EKU9003173C9|EKU9003173C9FRNN09|1||
' 507|4199800|IM|2006-7888">
' 507|4199800|MS|2">
' 800|4199800|1">
' 801|M3621037.222|1|5|011|

' This is the contents after signing

' 500|1|3621|4199800|400||
' 601|3621|4199800|400|IN|1||EKU9003173C9|EKU9003173C9FRNN09|1||
' 507|4199800|IM|2006-7888">
' 507|4199800|MS|2">
' 800|4199800|1|fhP2Ker54D2+3+UZch23F0E72 .... 9qNSPIuAqpj524qLZbbA==|30001000000500003416|
' 801|M3621037.222|1|5|011|


' First create the text to be signed.
Dim bCRLF As Boolean = True
Dim sb As New Chilkat.StringBuilder
' Use CRLF line endings.
sb.AppendLine("500|1|3621|4199800|400||",bCRLF)
sb.AppendLine("601|3621|4199800|400|IN|1||EKU9003173C9|EKU9003173C9FRNN09|1||",bCRLF)
sb.AppendLine("507|4199800|IM|2006-7888">",bCRLF)
sb.AppendLine("507|4199800|MS|2">",bCRLF)

' Generate the MD5 hash of what we have so far..
Dim md5_base64 As String = sb.GetHash("md5","base64","utf-8")
Debug.WriteLine("MD5 hash = " & md5_base64)

' Complete the original file.
' After signing, we'll update the BASE64_SIGNATURE and CERT_SERIAL
sb.AppendLine("800|4199800|1|BASE64_SIGNATURE|CERT_SERIAL|",bCRLF)
sb.AppendLine("801|M3621037.222|1|5|011|",bCRLF)


' We're going to sign the MD5 hash using the private key.
Dim privKey As New Chilkat.PrivateKey
success = privKey.LoadAnyFormatFile("qa_data/certs/mexico_test/Certificados_de_Prueba/Certificados_Pruebas/Personas Morales/EKU9003173C9_20230517223532/CSD_EKU9003173C9_20230517223903/CSD_Sucursal_1_EKU9003173C9_20230517_223850.key","12345678a")
If (success = False) Then
    Debug.WriteLine(privKey.LastErrorText)
    Exit Sub
End If


' Generate the ASN.1 to be signed.

' <sequence>
'     <sequence>
'         <oid>1.2.840.113549.2.5</oid>
'         <null/>
'     </sequence>
'     <octets>SwxHfaJhG+N3pPqay6UzVA==</octets>
' </sequence>

Dim xml As New Chilkat.Xml
xml.Tag = "sequence"
xml.UpdateChildContent("sequence|oid","1.2.840.113549.2.5")
xml.UpdateChildContent("sequence|null","")
xml.UpdateChildContent("octets",md5_base64)

Dim asn As New Chilkat.Asn
asn.LoadAsnXml(xml.GetXml())
Debug.WriteLine("ASN.1 = " & asn.GetEncodedDer("base64"))

' Sign with the private key.
Dim rsa As New Chilkat.Rsa
success = rsa.ImportPrivateKeyObj(privKey)
If (success = False) Then
    Debug.WriteLine(rsa.LastErrorText)
    Exit Sub
End If


' Create the opaque signature.
Dim bdSig As New Chilkat.BinData
bdSig.AppendEncoded(asn.GetEncodedDer("base64"),"base64")
success = rsa.OpenSslSignBd(bdSig)
If (success = False) Then
    Debug.WriteLine(rsa.LastErrorText)
    Exit Sub
End If


' bd now contains the opaque signature, which embeds the ASN.1, which contains the MD5 hash.
' We're going to add this line:
' 800|4199800|1|BASE64_SIGNATURE|CERT_SERIAL_NUM|

Dim cert As New Chilkat.Cert
success = cert.LoadFromFile("qa_data/certs/mexico_test/Certificados_de_Prueba/Certificados_Pruebas/Personas Morales/EKU9003173C9_20230517223532/CSD_EKU9003173C9_20230517223903/CSD_Sucursal_1_EKU9003173C9_20230517_223850.cer")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If

Dim serialHex As String = cert.SerialNumber
' The serial in hex form looks like this:   3330303031303030303030353030303033343136
' Decode to us-ascii.
Dim sbSerial As New Chilkat.StringBuilder
sbSerial.DecodeAndAppend(serialHex,"hex","us-ascii")
Debug.WriteLine("serial number in us-ascii: " & sbSerial.GetAsString())

Dim numReplaced As Integer = sb.Replace("CERT_SERIAL",sbSerial.GetAsString())
numReplaced = sb.Replace("BASE64_SIGNATURE",bdSig.GetEncoded("base64"))

Debug.WriteLine("------------------------------------")
Debug.WriteLine("Result:")
Debug.WriteLine(sb.GetAsString())