* Create P256 keypairs for dpop (#29)

* * Create P256 keypairs for dpop
* Create jwt

* code clean up

* code clean up

Author: Ethella

Sources/MagicSDK/Core/Provider/RpcProvider.swift

@@ -49,7 +49,7 @@ public class RpcProvider: NetworkClient, Web3Provider {
         let newRequest = RPCRequest(method: request.method, params: request.params)
 
         // construct message data
-        let eventMessage = RequestData(msgType: "\(msgType.rawValue)-\(urlBuilder.encodedParams)", payload: newRequest)
+        let eventMessage = MagicRequestData(msgType: "\(msgType.rawValue)-\(urlBuilder.encodedParams)", payload: newRequest, rt: nil, jwt: createJwt())
 
         // encode to JSON
         firstly {
@@ -66,7 +66,7 @@ public class RpcProvider: NetworkClient, Web3Provider {
 
                 // Decode JSON string into string
                 do {
-                let rpcResponse = try self.decoder.decode(ResponseData<RPCResponse<Result>>.self, from: jsonData)
+                let rpcResponse = try self.decoder.decode(MagicResponseData<RPCResponse<Result>>.self, from: jsonData)
                     let result = Web3Response<Result>(rpcResponse: rpcResponse.response)
                     response(result)
                 } catch {

Sources/MagicSDK/Core/Relayer/Types/BasicTypes.swift

@@ -20,14 +20,17 @@ enum OutboundMessageType: String, CaseIterable {
     case MAGIC_HANDLE_REQUEST
 }
 
-struct RequestData<T: Codable>: Codable {
+struct MagicRequestData<T: Codable>: Codable {
 
     let msgType: String
     let payload: T
+    let rt: String?
+    let jwt: String?
 }
 
-struct ResponseData<T: Codable>: Codable {
+struct MagicResponseData<T: Codable>: Codable {
 
     let msgType: String
     let response: T
+    let rt: String?
 }

Sources/MagicSDK/Core/Relayer/Types/DPop.swift

@@ -0,0 +1,79 @@
+//
+//  File.swift
+//
+//
+//  Created by Wentao Liu on 7/11/23.
+//
+
+import Foundation
+import CryptoKit
+
+
+func base64UrlEncoded(_ data: Data) -> String {
+    var b64 = data.base64EncodedString()
+    b64 = b64.replacingOccurrences(of: "+", with: "-")
+    b64 = b64.replacingOccurrences(of: "/", with: "_")
+    b64 = b64.replacingOccurrences(of: "=", with: "")
+    return b64
+}
+
+func createJwt()  -> String?{
+    var error: Unmanaged<CFError>?
+
+    do {
+        let privateKey = try retrieveKeyFromKeyChain()
+
+        // Get the public key.
+        let publicKey = privateKey.publicKey
+
+        // Get the raw representation of the public key.
+        let rawPublicKey = publicKey.rawRepresentation
+
+        // Extract the x and y coordinates.
+        let xCoordinateData = rawPublicKey[1..<33]
+        let yCoordinateData = rawPublicKey[33..<65]
+
+        // If you need base64-encoded strings for JWK:
+        let xCoordinateBase64 = base64UrlEncoded(xCoordinateData)
+        let yCoordinateBase64 = base64UrlEncoded(yCoordinateData)
+        // Convert the public key to JWK format.
+        // construct headers
+        var headers: [String: Any] = ["typ": "dpop+jwt", "alg": "ES256"]
+        headers["jwk"]  = [
+            "kty": "EC",
+            "crv": "P-256",
+            "x": xCoordinateBase64,
+            "y": yCoordinateBase64
+        ] as [String : Any]
+
+         let headersData = try JSONSerialization.data(withJSONObject: headers)
+         let headersB64 = base64UrlEncoded(headersData)
+
+
+        // construct claims
+        let iat = Int(Date().timeIntervalSince1970)
+        let jti = UUID().uuidString.lowercased()
+
+        let claims: [String: Any] = ["iat": iat, "jti": jti]
+        let claimsData = try JSONSerialization.data(withJSONObject: claims)
+        let claimsB64 = base64UrlEncoded(claimsData)
+
+        /// sign
+        let signingInput = headersB64 + "." + claimsB64
+        let signingInputData = signingInput.data(using: .utf8)!
+
+        let signature = try! privateKey.signature(for: signingInputData)
+
+        let signatureB64 = base64UrlEncoded(signature.rawRepresentation)
+
+        let jwt = signingInput + "." + signatureB64
+
+        return jwt
+
+    } catch {
+        // silently handled error
+        return nil
+    }
+
+}
+