From f6a94ef15b67f5b14d069e4bc99ecf328002ad8e Mon Sep 17 00:00:00 2001
From: dtsiflit <dimitri.tsiflitzis@netcompany.com>
Date: Fri, 13 Dec 2024 11:06:42 +0200
Subject: [PATCH] [fix] async signer updates

---
 Sources/Entities/Encryption/BindingKey.swift | 19 +++----
 Tests/Constants/TestsConstants.swift         | 56 ++++++++++++++++++--
 Tests/Wallet/VCIFlowWithOffer.swift          | 51 +++++++++++++++++-
 3 files changed, 107 insertions(+), 19 deletions(-)

diff --git a/Sources/Entities/Encryption/BindingKey.swift b/Sources/Entities/Encryption/BindingKey.swift
index d92fecd..8765815 100644
--- a/Sources/Entities/Encryption/BindingKey.swift
+++ b/Sources/Entities/Encryption/BindingKey.swift
@@ -185,19 +185,12 @@ extension BindingKey {
       return secKeySigner
       
     } else if case let .custom(customAsyncSigner) = privateKey {
-      let signingInput: Data? = [
-        header as DataConvertible,
-        payload as DataConvertible
-      ].map {
-        $0.data().base64URLEncodedString()
-      }
-      .joined(separator: ".").data(using: .ascii)
-      
-      guard let signingInput = signingInput else {
-        throw ValidationError.error(reason: "Invalid signing input fopr signing data")
-      }
+      let headerData = header as DataConvertible
+      let signature = try await customAsyncSigner.signAsync(
+        headerData.data(),
+        payload.data()
+      )
       
-      let signature = try await customAsyncSigner.signAsync(signingInput)
       let customSigner = PrecomputedSigner(
         signature: signature,
         algorithm: signatureAlgorithm
@@ -225,5 +218,5 @@ class PrecomputedSigner: JOSESwift.SignerProtocol {
 }
 
 public protocol AsyncSignerProtocol {
-	func signAsync(_ signingInput: Data) async throws -> Data
+  func signAsync(_ header: Data, _ payload: Data) async throws -> Data
 }
diff --git a/Tests/Constants/TestsConstants.swift b/Tests/Constants/TestsConstants.swift
index c29c2af..6da786a 100644
--- a/Tests/Constants/TestsConstants.swift
+++ b/Tests/Constants/TestsConstants.swift
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 import Foundation
+import JOSESwift
+
 @testable import OpenID4VCI
 
 let CREDENTIAL_ISSUER_PUBLIC_URL = "https://dev.issuer-backend.eudiw.dev"
@@ -77,7 +79,7 @@ let MDL_CredentialOffer = """
 
 let config: OpenId4VCIConfig = .init(
   clientId: "wallet-dev",
-  authFlowRedirectionURI: URL(string: "urn:ietf:wg:oauth:2.0:oob")!, 
+  authFlowRedirectionURI: URL(string: "urn:ietf:wg:oauth:2.0:oob")!,
   authorizeIssuanceConfig: .favorScopes
 )
 
@@ -146,7 +148,7 @@ struct TestsConstants {
         path: "credential_issuer_metadata",
         extension: "json"
       )
-    ))
+      ))
     
     let authorizationServerMetadataResolver = AuthorizationServerMetadataResolver(
       oidcFetcher: Fetcher<OIDCProviderMetadata>(session: NetworkingMock(
@@ -179,7 +181,7 @@ struct TestsConstants {
         path: "openid-credential-issuer_no_encryption",
         extension: "json"
       )
-    ))
+      ))
     
     let authorizationServerMetadataResolver = AuthorizationServerMetadataResolver(
       oidcFetcher: Fetcher<OIDCProviderMetadata>(session: NetworkingMock(
@@ -212,7 +214,7 @@ struct TestsConstants {
         path: "openid-credential-issuer_no_encryption_batch",
         extension: "json"
       )
-    ))
+      ))
     
     let authorizationServerMetadataResolver = AuthorizationServerMetadataResolver(
       oidcFetcher: Fetcher<OIDCProviderMetadata>(session: NetworkingMock(
@@ -245,7 +247,7 @@ struct TestsConstants {
         path: "credential_issuer_metadata",
         extension: "json"
       )
-    ))
+      ))
     
     let authorizationServerMetadataResolver = AuthorizationServerMetadataResolver(
       oidcFetcher: Fetcher<OIDCProviderMetadata>(session: NetworkingMock(
@@ -272,3 +274,47 @@ struct TestsConstants {
     ).get()
   }
 }
+
+class TestSinger: AsyncSignerProtocol {
+  let privateKey: SecKey
+  
+  init(privateKey: SecKey) {
+    self.privateKey = privateKey
+  }
+  
+  func signAsync(_ header: Data, _ payload: Data) async throws -> Data {
+    
+    guard
+      let jwsHeader = JWSHeader(header),
+      let algorithm = jwsHeader.algorithm
+    else {
+      throw NSError(
+        domain: "SignerErrorDomain",
+        code: 1,
+        userInfo: [NSLocalizedDescriptionKey: "Unable to create signer"]
+      )
+    }
+    
+    /// Create the signer
+    guard let signer = Signer(
+      signatureAlgorithm: algorithm,
+      key: privateKey
+    ) else {
+      throw NSError(
+        domain: "SignerErrorDomain",
+        code: 1,
+        userInfo: [NSLocalizedDescriptionKey: "Unable to create signer"]
+      )
+    }
+    
+    let jws = try JWS(
+      header: jwsHeader,
+      payload: .init(
+        payload
+      ),
+      signer: signer
+    )
+    
+    return jws.signature
+  }
+}
diff --git a/Tests/Wallet/VCIFlowWithOffer.swift b/Tests/Wallet/VCIFlowWithOffer.swift
index 0cc1052..7ca2b51 100644
--- a/Tests/Wallet/VCIFlowWithOffer.swift
+++ b/Tests/Wallet/VCIFlowWithOffer.swift
@@ -74,6 +74,55 @@ class VCIFlowWithOffer: XCTestCase {
     XCTAssert(true)
   }
   
+  func testWithOfferSdJWTWithSigner() async throws {
+    
+    let privateKey = try KeyController.generateECDHPrivateKey()
+    let publicKey = try KeyController.generateECDHPublicKey(from: privateKey)
+    
+    let alg = JWSAlgorithm(.ES256)
+    let publicKeyJWK = try ECPublicKey(
+      publicKey: publicKey,
+      additionalParameters: [
+        "alg": alg.name,
+        "use": "sig",
+        "kid": UUID().uuidString
+      ])
+    
+    let bindingKey: BindingKey = .jwk(
+      algorithm: alg,
+      jwk: publicKeyJWK,
+      privateKey: .custom(
+        TestSinger(
+          privateKey: privateKey
+        )
+      )
+    )
+    
+    let user = ActingUser(
+      username: "tneal",
+      password: "password"
+    )
+    
+    let wallet = Wallet(
+      actingUser: user,
+      bindingKeys: [bindingKey],
+      dPoPConstructor: nil,
+      session: Wallet.walletSession
+    )
+    
+    do {
+      try await walletInitiatedIssuanceWithOfferSdJWT(
+        wallet: wallet
+      )
+    } catch {
+      
+      XCTExpectFailure()
+      XCTAssert(false, error.localizedDescription)
+    }
+    
+    XCTAssert(true)
+  }
+  
   func testWithOfferMdoc() async throws {
     
     let privateKey = try KeyController.generateECDHPrivateKey()
@@ -315,7 +364,7 @@ private func walletInitiatedIssuanceWithOfferSdJWT(
     scope: PID_SdJwtVC_config_id,
     claimSet: claimSet
   )
-
+  
   print("--> [ISSUANCE] Issued credential: \(credential)")
 }