B4X Requires Chilkat v11.0.0+

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

See more OpenSSL Examples

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

B4X

Dim success As Boolean = False

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

Dim pkey As ChilkatPrivateKey
pkey.Initialize("pkey")

'  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 = False Then
    Log(pkey.LastErrorText)
    Return
End If


'  Assuming this is an RSA private key..
Dim rsa As ChilkatRsa
rsa.Initialize

'  Import the private key into the RSA object:
success = rsa.UsePrivateKey(pkey)
If success = False Then
    Log(rsa.LastErrorText)
    Return
End If


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

'  SHA1 hash and sign, and return base64.
rsa.EncodingMode = "base64"
Dim b64sig As String = rsa.SignStringENC("2018-05-18,2018-05-18T11:22:19;FAC 001/18;53.00;", "sha1")
Log(b64sig)

'  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.