(Visual Basic 6.0) Sign Mexico Pedimento

Add a signature to a Mexico pedimento file.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim success As Long

' 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 Long
bCRLF = 1
Dim sb As New ChilkatStringBuilder
' Use CRLF line endings.
success = sb.AppendLine("500|1|3621|4199800|400||",bCRLF)
success = sb.AppendLine("601|3621|4199800|400|IN|1||EKU9003173C9|EKU9003173C9FRNN09|1||",bCRLF)
success = sb.AppendLine("507|4199800|IM|2006-7888">",bCRLF)
success = sb.AppendLine("507|4199800|MS|2">",bCRLF)

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

' Complete the original file.
' After signing, we'll update the BASE64_SIGNATURE and CERT_SERIAL
success = sb.AppendLine("800|4199800|1|BASE64_SIGNATURE|CERT_SERIAL|",bCRLF)
success = 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 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 = 0) Then
    Debug.Print 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 ChilkatXml
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 ChilkatAsn
success = asn.LoadAsnXml(xml.GetXml())
Debug.Print "ASN.1 = " & asn.GetEncodedDer("base64")

' Sign with the private key.
Dim rsa As New ChilkatRsa
success = rsa.ImportPrivateKeyObj(privKey)
If (success = 0) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

' Create the opaque signature.
Dim bdSig As New ChilkatBinData
success = bdSig.AppendEncoded(asn.GetEncodedDer("base64"),"base64")
success = rsa.OpenSslSignBd(bdSig)
If (success = 0) Then
    Debug.Print 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 ChilkatCert
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 = 0) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

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

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

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