(PureBasic) 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 PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkPrivateKey.pb"
IncludeFile "CkRsa.pb"

Procedure ChilkatExample()

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

    pkey.i = CkPrivateKey::ckCreate()
    If pkey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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.i = CkPrivateKey::ckLoadAnyFormatFile(pkey,"qa_data/rsa/rsaPrivKey_secret.pem","secret")
    If success <> 1
        Debug CkPrivateKey::ckLastErrorText(pkey)
        CkPrivateKey::ckDispose(pkey)
        ProcedureReturn
    EndIf

    ; Assuming this is an RSA private key..
    rsa.i = CkRsa::ckCreate()
    If rsa.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Import the private key into the RSA object:
    success = CkRsa::ckImportPrivateKeyObj(rsa,pkey)
    If success <> 1
        Debug CkRsa::ckLastErrorText(rsa)
        CkPrivateKey::ckDispose(pkey)
        CkRsa::ckDispose(rsa)
        ProcedureReturn
    EndIf

    ; OpenSSL uses big-endian.
    CkRsa::setCkLittleEndian(rsa, 0)

    ; SHA1 hash and sign, and return base64.
    CkRsa::setCkEncodingMode(rsa, "base64")
    b64sig.s = CkRsa::ckSignStringENC(rsa,"2018-05-18,2018-05-18T11:22:19;FAC 001/18;53.00;","sha1")
    Debug 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.


    CkPrivateKey::ckDispose(pkey)
    CkRsa::ckDispose(rsa)


    ProcedureReturn
EndProcedure