(DataFlex) 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

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

Use ChilkatAx-9.5.0-win32.pkg

Procedure Test
    Variant vPkey
    Handle hoPkey
    Boolean iSuccess
    Handle hoRsa
    String sB64sig
    String sTemp1

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

    Get Create (RefClass(cComChilkatPrivateKey)) To hoPkey
    If (Not(IsComObjectCreated(hoPkey))) Begin
        Send CreateComObject of hoPkey
    End

    // 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.
    Get ComLoadAnyFormatFile Of hoPkey "qa_data/rsa/rsaPrivKey_secret.pem" "secret" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoPkey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Assuming this is an RSA private key..
    Get Create (RefClass(cComChilkatRsa)) To hoRsa
    If (Not(IsComObjectCreated(hoRsa))) Begin
        Send CreateComObject of hoRsa
    End

    // Import the private key into the RSA object:
    Get pvComObject of hoPkey to vPkey
    Get ComImportPrivateKeyObj Of hoRsa vPkey To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRsa To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // OpenSSL uses big-endian.
    Set ComLittleEndian Of hoRsa To False

    // SHA1 hash and sign, and return base64.
    Set ComEncodingMode Of hoRsa To "base64"
    Get ComSignStringENC Of hoRsa "2018-05-18,2018-05-18T11:22:19;FAC 001/18;53.00;" "sha1" To sB64sig
    Showln sB64sig

    // 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.


End_Procedure