Visual Basic 6.0 Requires Chilkat v11.0.0+

Ibanity HTTP Signature for XS2A, Isabel Connect, Ponto Connect

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Demonstrates how to add a Signature header for Ibanity HTTP requests. Visual Basic 6.0

Dim success As Long
success = 0

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

'  In order to sign your HTTP requests, you have to add 2 headers to the HTTP request: Digest: the digest of the request payload and Signature: the actual signature of the request. 

'  POST /xs2a/customer-access-tokens HTTP/1.1
'  Host: api.ibanity.com
'  Content-Type: application/json
'  Digest: SHA-512=z4PhNX7vuL3xVChQ1m2AB9Yg5AULVxXcg/SpIdNs6c5H0NE8XYXysP+DGNKHfuwvY7kxvUdBeoGlODJ6+SfaPg==
'  Ibanity-Idempotency-Key: 61f02718-eeee-46e1-b5eb-e8fd6e799c2d
'  Signature: keyId="62f02718-eeee-46e1-b5eb-e8fd6e799c2e",created=1599659223,algorithm="hs2019",headers="(request-target) host digest (created) ibanity-idempotency-key",signature="SjWJWbWN7i0...zsbM="
'  
'  {"data":{"type":"customerAccessToken", "attributes":{"applicationCustomerReference":"15874569"}}}

'  The payload (body) of the above HTTP request is the JSON.
'  Build the JSON above.
'  Use this online tool to generate code from sample JSON: 
'  Generate Code to Create JSON
Dim json As New ChilkatJsonObject
success = json.UpdateString("data.type","customerAccessToken")
success = json.UpdateString("data.attributes.applicationCustomerReference","15874569")

Dim payload As String
payload = json.Emit()
Debug.Print "payload = " & payload

'  Step 1: Build the (created) virtual header

Dim dtNow As New CkDateTime
success = dtNow.SetFromCurrentSystemTime()
Dim created As String
created = dtNow.GetAsUnixTimeStr(0)
Debug.Print "created = " & created

'  Step 2: Build the Digest header
Dim crypt As New ChilkatCrypt2
crypt.HashAlgorithm = "sha512"
crypt.EncodingMode = "base64"
crypt.Charset = "utf-8"

Dim sbDigestHdrValue As New ChilkatStringBuilder
success = sbDigestHdrValue.Append("SHA-512=")
success = sbDigestHdrValue.Append(crypt.HashStringENC(json.Emit()))

Debug.Print sbDigestHdrValue.GetAsString()

'  Step 3: Build the (request target) virtual header

'  In order to build the signature you will need a virtual header named (request-target) (the parentheses are important). 
'  The (request-target) is the string concatenation of the HTTP method (in lowercase) with the path and query parameters.
Dim request_target As String
request_target = "post /xs2a/customer-access-tokens"

'  Step 4: Build the signing string

'  The signing string is the concatenation of the signed header names (in lowercase) and values separated by a LF.

'  You must always sign the following headers: (request-target), host, (created), digest. 
'  If used, you must also sign the authorization header and any ibanity-* headers, such as ibanity-idempotency-key. 

Dim sbSigningString As New ChilkatStringBuilder
success = sbSigningString.Append("(request-target): ")
success = sbSigningString.AppendLine(request_target,0)
success = sbSigningString.Append("host: ")
success = sbSigningString.AppendLine("api.ibanity.com",0)
success = sbSigningString.Append("digest: ")
success = sbSigningString.AppendLine(sbDigestHdrValue.GetAsString(),0)
success = sbSigningString.Append("(created): ")
success = sbSigningString.AppendLine(created,0)
success = sbSigningString.Append("ibanity-idempotency-key: ")
Dim idempotencyKey As String
idempotencyKey = crypt.GenerateUuid()
success = sbSigningString.Append(idempotencyKey)

'  Step 5: Build the signed headers list

'  To allow Ibanity to check the signed headers, you must provide a list of the header names. They should be lowercase and in the same order used to create the signing string. 
Dim signed_headers_list As String
signed_headers_list = "(request-target) host digest (created) ibanity-idempotency-key"

'  Step 6: Build the Signature header

'  This is where the real signing happens. The signature header is a combination of several sub-headers -
'  
'      keyId: the identifier for the application's signature certificate, obtained from the Developer Portal
'      algorithm: the digital signature algorithm used to generate the signature (must be hs2019)
'      headers: The list of HTTP headers created in step 5
'      signature: the Base64-encoded digital signature of the signing string created in step 4.

Dim privKey As New PrivateKey
success = privKey.LoadEncryptedPemFile("my_ibanity_signature_private_key.pem","pem_password")
If (success = 0) Then
    Debug.Print privKey.LastErrorText
    Exit Sub
End If

Dim rsa As New ChilkatRsa
rsa.PssSaltLen = 32
rsa.EncodingMode = "base64"
'  Use the RSASSA-PSS signature algorithm
rsa.PkcsPadding = 0

success = rsa.UsePrivateKey(privKey)
If (success = 0) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

'  Sign the signing string.
Dim sigBase64 As String
sigBase64 = rsa.SignStringENC(sbSigningString.GetAsString(),"sha-256")
If (rsa.LastMethodSuccess = 0) Then
    Debug.Print rsa.LastErrorText
    Exit Sub
End If

'  Build the signature header value.
Dim sbSigHeaderValue As New ChilkatStringBuilder
success = sbSigHeaderValue.Append("keyId=""")
'  Use your identifier for the application's signature certificate, obtained from the Developer Portal
success = sbSigHeaderValue.Append("62f02718-eeee-46e1-b5eb-e8fd6e799c2e")
success = sbSigHeaderValue.Append(""",created=")
success = sbSigHeaderValue.Append(created)
success = sbSigHeaderValue.Append(",algorithm=""hs2019"",headers=""")
success = sbSigHeaderValue.Append(signed_headers_list)
success = sbSigHeaderValue.Append(""",signature=""")
success = sbSigHeaderValue.Append(sigBase64)
success = sbSigHeaderValue.Append("""")

Debug.Print sbSigHeaderValue.GetAsString()