User-345719443 posted
I try to follow the following steps to validate an Authorization CODE:
To validate an Authorization Code issued from the Authorization Endpoint with an ID Token, the Client SHOULD do the following:
1-) Hash the octets of the ASCII representation of the code with the hash algorithm specified in JWA [JWA] for the alg Header Parameter of the ID Token's JOSE Header. For instance, if the alg is RS256, the hash algorithm
used is SHA-256.
2-) Take the left-most half of the hash and base64url encode it.
3-) The value of c_hash in the ID Token MUST match the value produced in the previous step if c_hash is present in the ID Token.
I have this CODE when I request an Authorization endpoint the first time to try authenticate a user from a WebForms Client :
code=0655d48df75629d9fdbd5a060141bf66ca04418a0e762a6a5e6382c2748753af
I have this C_HASH too that I can get from the id_token :
"c_hash": "QadHSCSim4aHM8q1F1F6Bg"
I'm trying to validate the CODE doing the next :
Private Shared Function IsValidAuthorizationCode(authorizationCode As String, stringIdTokenPayload As String) As Boolean
Dim serializer As New JavaScriptSerializer()
Dim BytesPayload As Byte() = Decode(stringIdTokenPayload)
Dim stringPayload As String = System.Text.ASCIIEncoding.ASCII.GetString(BytesPayload)
Dim deserialized_payload = serializer.Deserialize(Of Dictionary(Of String, Object))(stringPayload)
Dim c_hash = deserialized_payload.Item("c_hash").ToString()
Dim mySHA256 = SHA256Managed.Create()
Dim authorizationCodeOCTETS = Decode(authorizationCode)
Dim elemntsToIterate = mySHA256.ComputeHash(authorizationCodeOCTETS)
Dim length = elemntsToIterate.Length
Dim hashedCode(length/2 - 1) As Byte
Dim count = -1
For Each element As Byte in elemntsToIterate
count += 1
If count > 15 Then
hashedCode(count - 16) = element
End If
Next
Dim hashedCodeLikeString = Convert.ToBase64String(hashedCode)
If hashedCodeLikeString.Length <> hashedCode.Length
Return False
Dim result As Boolean = True
For value As Integer = 0 To hashedCodeLikeString.Length
If (hashedCodeLikeString(value) <> hashedCode(value)) Then
result = False
Exit For
End If
Next
Return result
End Function
But I don't get the expected result. I need to get a TRUE value but I get a FALSE. I think that I am doing something wrong but I don't see what it is. Any help, please?
Thank you very much in advance.
