Xbase++ Requires Chilkat v11.0.0+
Ibanity HTTP Signature for XS2A, Isabel Connect, Ponto Connect

Demonstrates how to add a Signature header for Ibanity HTTP requests.
Chilkat Xbase++ Downloads

Xbase++
LOCAL nSuccess
LOCAL oJson
LOCAL cPayload
LOCAL oDtNow
LOCAL cCreated
LOCAL oCrypt
LOCAL oSbDigestHdrValue
LOCAL cRequest_target
LOCAL oSbSigningString
LOCAL cIdempotencyKey
LOCAL cSigned_headers_list
LOCAL oPrivKey
LOCAL oRsa
LOCAL cSigBase64
LOCAL oSbSigHeaderValue

nSuccess := 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
oJson := CreateObject("Chilkat.JsonObject")
oJson:UpdateString("data.type", "customerAccessToken")
oJson:UpdateString("data.attributes.applicationCustomerReference", "15874569")

cPayload := oJson:Emit()
? "payload = " + cPayload

//  Step 1: Build the (created) virtual header

oDtNow := CreateObject("Chilkat.CkDateTime")
oDtNow:SetFromCurrentSystemTime()
cCreated := oDtNow:GetAsUnixTimeStr(0)
? "created = " + cCreated

//  Step 2: Build the Digest header
oCrypt := CreateObject("Chilkat.Crypt2")
oCrypt:HashAlgorithm := "sha512"
oCrypt:EncodingMode := "base64"
oCrypt:Charset := "utf-8"

oSbDigestHdrValue := CreateObject("Chilkat.StringBuilder")
oSbDigestHdrValue:Append("SHA-512=")
oSbDigestHdrValue:Append(oCrypt:HashStringENC(oJson:Emit()))

? oSbDigestHdrValue: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.
cRequest_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. 

oSbSigningString := CreateObject("Chilkat.StringBuilder")
oSbSigningString:Append("(request-target): ")
oSbSigningString:AppendLine(cRequest_target, 0)
oSbSigningString:Append("host: ")
oSbSigningString:AppendLine("api.ibanity.com", 0)
oSbSigningString:Append("digest: ")
oSbSigningString:AppendLine(oSbDigestHdrValue:GetAsString(), 0)
oSbSigningString:Append("(created): ")
oSbSigningString:AppendLine(cCreated, 0)
oSbSigningString:Append("ibanity-idempotency-key: ")
cIdempotencyKey := oCrypt:GenerateUuid()
oSbSigningString:Append(cIdempotencyKey)

//  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. 
cSigned_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.

oPrivKey := CreateObject("Chilkat.PrivateKey")
nSuccess := oPrivKey:LoadEncryptedPemFile("my_ibanity_signature_private_key.pem", "pem_password")
IF (nSuccess == 0)
    ? oPrivKey:LastErrorText
    oJson:destroy()
    oDtNow:destroy()
    oCrypt:destroy()
    oSbDigestHdrValue:destroy()
    oSbSigningString:destroy()
    oPrivKey:destroy()
    RETURN
ENDIF

oRsa := CreateObject("Chilkat.Rsa")
oRsa:PssSaltLen := 32
oRsa:EncodingMode := "base64"
//  Use the RSASSA-PSS signature algorithm
oRsa:PkcsPadding := 0

nSuccess := oRsa:UsePrivateKey(oPrivKey)
IF (nSuccess == 0)
    ? oRsa:LastErrorText
    oJson:destroy()
    oDtNow:destroy()
    oCrypt:destroy()
    oSbDigestHdrValue:destroy()
    oSbSigningString:destroy()
    oPrivKey:destroy()
    oRsa:destroy()
    RETURN
ENDIF

//  Sign the signing string.
cSigBase64 := oRsa:SignStringENC(oSbSigningString:GetAsString(), "sha-256")
IF (oRsa:LastMethodSuccess == 0)
    ? oRsa:LastErrorText
    oJson:destroy()
    oDtNow:destroy()
    oCrypt:destroy()
    oSbDigestHdrValue:destroy()
    oSbSigningString:destroy()
    oPrivKey:destroy()
    oRsa:destroy()
    RETURN
ENDIF

//  Build the signature header value.
oSbSigHeaderValue := CreateObject("Chilkat.StringBuilder")
oSbSigHeaderValue:Append('keyId="')
//  Use your identifier for the application's signature certificate, obtained from the Developer Portal
oSbSigHeaderValue:Append("62f02718-eeee-46e1-b5eb-e8fd6e799c2e")
oSbSigHeaderValue:Append('",created=')
oSbSigHeaderValue:Append(cCreated)
oSbSigHeaderValue:Append(',algorithm="hs2019",headers="')
oSbSigHeaderValue:Append(cSigned_headers_list)
oSbSigHeaderValue:Append('",signature="')
oSbSigHeaderValue:Append(cSigBase64)
oSbSigHeaderValue:Append('"')

? oSbSigHeaderValue:GetAsString()

oJson:destroy()
oDtNow:destroy()
oCrypt:destroy()
oSbDigestHdrValue:destroy()
oSbSigningString:destroy()
oPrivKey:destroy()
oRsa:destroy()
oSbSigHeaderValue:destroy()