Classic ASP

Create a Hash Signature for Value Added Tax Audit SOAP Message for Angola

Demonstrates how to create a hash signature that is required in Value Added Tax Audit Files in Angola, Africa.

It is the following two instructions that should be used to create a hash value to be put into a <hash></hash> field in SOAP XML file containing the tax data for the VAT authorities:

openssl dgst -shal -sign private.pem -outRegisto1.shal Registo1.txt

then

openssl enc -base64 - in Registo1.shal -out Registo1.b64 -A

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Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

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

set pkey = Server.CreateObject("Chilkat.PrivateKey")

' Load the private key from an PEM file.
' Provide the password in the 2nd argument.
' If no password is needed, just pass an empty string.
success = pkey.LoadAnyFormatFile("qa_data/rsa/rsaPrivKey_secret.pem","secret")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( pkey.LastErrorText) & "</pre>"
    Response.End
End If

' Assuming this is an RSA private key..
set rsa = Server.CreateObject("Chilkat.Rsa")

' Import the private key into the RSA object:
success = rsa.UsePrivateKey(pkey)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.End
End If

' OpenSSL uses big-endian.
rsa.LittleEndian = 0

' SHA1 hash and sign, and return base64.
rsa.EncodingMode = "base64"
b64sig = rsa.SignStringENC("2018-05-18,2018-05-18T11:22:19;FAC 001/18;53.00;","sha1")
Response.Write "<pre>" & Server.HTMLEncode( b64sig) & "</pre>"

' The signature is equal in size to your private key.  For example, if you have a 1024-bit RSA key,
' then 1024 bits = 128 bytes.   When 128 bytes is base64 encoded, the result is a string approximately
' 4/3rds the size of the original.  128 * 4 / 3 = (approximately) 172 bytes.

' If your RSA key is 2048-bits, then your signature will be twice as long.

%>
</body>
</html>