diff --git a/PatientScannerDemo/COSE.swift b/PatientScannerDemo/COSE.swift
new file mode 100644
index 0000000..73d15ba
--- /dev/null
+++ b/PatientScannerDemo/COSE.swift
@@ -0,0 +1,69 @@
+//
+//  COSE.swift
+//  PatientScannerDemo
+//
+//  Created by Yannick Spreen on 4/14/21.
+//
+
+import Foundation
+import SwiftCBOR
+import CryptoKit
+
+struct COSE {
+  public static func verify(_ cbor: CBOR, with xHex: String, and yHex: String) -> Bool {
+    let COSE_TAG = UInt64(18)
+    let COSE_PHDR_SIG = CBOR.unsignedInt(1)
+
+    guard
+      case let CBOR.tagged(tag, cborElement) = cbor,
+      tag.rawValue == COSE_TAG, // SIGN1
+      case let CBOR.array(array) = cborElement,
+      case let CBOR.byteString(protectedBytes) = array[0],
+      case let CBOR.map(unprotected) = array[1],
+      case let CBOR.byteString(payloadBytes) = array[2],
+      case let CBOR.byteString(signature) = array[3],
+      let protected = try? CBOR.decode(protectedBytes),
+      let payload = try? CBOR.decode(payloadBytes),
+      case let CBOR.map(protectedMap) = protected,
+      let sig = protectedMap[COSE_PHDR_SIG]
+    else {
+      return false
+    }
+
+    let signedPayload: [UInt8] = CBOR.encode(
+      [
+        "Signature1",
+        array[0],
+        CBOR.byteString([]),
+        array[2]
+      ]
+    )
+    let d = Data(bytes: signedPayload, count: signedPayload.count)
+    let digest = SHA256.hash(data: signedPayload)
+    guard
+      let signatureForData = try? P256.Signing.ECDSASignature(rawRepresentation: signature)
+    else {
+      return false
+    }
+
+    struct TE : CustomStringConvertible {
+      var description: String
+      let kid : String
+      //let coord : Array()
+    }
+
+    let x = Data(hexString: xHex)?.uint ?? []
+    let y = Data(hexString: yHex)?.uint ?? []
+    let rawk: [UInt8] = [04] + x + y
+    let _ = (unprotected, sig, d, payload) // unused
+
+    if
+      rawk.count == 32+32+1,
+      let publicKey = try? P256.Signing.PublicKey(x963Representation: rawk),
+      publicKey.isValidSignature(signatureForData, for: digest)
+    {
+      return true
+    }
+    return false
+  }
+}
diff --git a/PatientScannerDemoTests/EHNTests.swift b/PatientScannerDemoTests/EHNTests.swift
index fcc69a7..92b07f7 100644
--- a/PatientScannerDemoTests/EHNTests.swift
+++ b/PatientScannerDemoTests/EHNTests.swift
@@ -12,7 +12,7 @@ import SwiftCBOR
 
 var barcode = "HC1NCFY70R30FFWTWGSLKC 4O992$V M63TMF2V*D9LPC.3EHPCGEC27B72VF/347O4-M6Y9M6FOYG4ILDEI8GR3ZI$15MABL:E9CVBGEEWRMLE C39S0/ANZ52T82Z-73D63P1U 1$PKC 72H2XX09WDH889V5"
 
-let trust_json = """
+let trustJson = """
 [
   {
     \"kid\" : \"DEFBBA3378B322F5\",
@@ -33,10 +33,8 @@ let trust_json = """
 
 
 class EHNTests: XCTestCase {
-
   func test_cose() throws {
     let COSE_TAG = UInt64(18)
-    let COSE_PHDR_SIG = CBOR.unsignedInt(1)
     let COSE_PHDR_KID = CBOR.unsignedInt(4)
 
     // Remove HC1 header if any
@@ -47,7 +45,7 @@ class EHNTests: XCTestCase {
     guard
       let compressed = try? barcode.fromBase45()
     else {
-      assert(false)
+      XCTAssert(false)
       return
     }
 
@@ -55,91 +53,48 @@ class EHNTests: XCTestCase {
     let decoder = SwiftCBOR.CBORDecoder(input: data.uint)
 
     guard
-      let cose = try? decoder.decodeItem(),
-      case let CBOR.tagged(tag, cborElement) = cose,
+      let cbor = try? decoder.decodeItem(),
+      case let CBOR.tagged(tag, cborElement) = cbor,
       tag.rawValue == COSE_TAG, // SIGN1
       case let CBOR.array(array) = cborElement,
       case let CBOR.byteString(protectedBytes) = array[0],
-      case let CBOR.map(unprotected) = array[1],
       case let CBOR.byteString(payloadBytes) = array[2],
-      case let CBOR.byteString(signature) = array[3],
       let protected = try? CBOR.decode(protectedBytes),
       let payload = try? CBOR.decode(payloadBytes),
       case let CBOR.map(protectedMap) = protected
     else {
-      assert(false)
+      XCTAssert(false)
       return
     }
-    var kid: [UInt8] = []
-    let sig = protectedMap[COSE_PHDR_SIG]!
-
-    print("SIG: ", sig)
-    if case let CBOR.byteString(k) = protectedMap[COSE_PHDR_KID] ?? .null {
-      kid = k
-    } else {
-      assert(false)
+    guard case let CBOR.byteString(kid) = protectedMap[COSE_PHDR_KID] ?? .null else {
+      XCTAssert(false)
+      return
     }
 
-    print("Signature: ", signature)
-    print("Payload: ", payload)
-    print("KID: ", kid)
-
-    let externalData = CBOR.byteString([])
-    let signed_payload: [UInt8] = CBOR.encode(
-      [
-        "Signature1",
-        array[0],
-        externalData,
-        array[2]
-      ]
-    )
-    let d = Data(bytes: signed_payload, count: signed_payload.count)
-    print("Signing: ", d.base64EncodedString())
-    let digest = SHA256.hash(data: signed_payload)
-    print("Digest: ", digest)
-
-    let signatureForData = try! P256.Signing.ECDSASignature(rawRepresentation: signature)
-
-    // use KID to find the right X,Y coordinates from the JSON
-    //
-    struct TE : CustomStringConvertible {
-      var description: String
-      let kid : String
-      //let coord : Array()
+    guard
+      let trustData = trustJson.data(using: .utf8),
+      let trustSerialization = try? JSONSerialization.jsonObject(with: trustData, options: []),
+      let trust = trustSerialization as? [[String: Any]]
+    else {
+      XCTAssert(false)
+      return
     }
-    var x: [UInt8] = []
-    var y: [UInt8] = []
-
-    let _ = unprotected // unused
-
-    if let trust = try? JSONSerialization.jsonObject(with: trust_json.data(using: .utf8)!, options: []) as? [[String: Any]] {
-      for case let elem: Dictionary in trust {
-        if kid == Data(hexString: elem["kid"] as! String)?.uint {
-          print("We know this KID - check if this sig works...")
-          x = Data(hexString: ((elem["coord"] as! Array<Any>)[0] as? String) ?? "")?.uint ?? []
-          y = Data(hexString: ((elem["coord"] as! Array<Any>)[1] as? String) ?? "")?.uint ?? []
-
-          var rawk: [UInt8] = [04]
-          rawk.append(contentsOf: x)
-          rawk.append(contentsOf: y)
-          XCTAssert(rawk.count == 32+32+1)
-
-          if
-            let publicKey = try? P256.Signing.PublicKey(x963Representation: rawk),
-            publicKey.isValidSignature(signatureForData, for: digest)
-          {
-            print("All is WELL !")
-
-            print("Payload (decoded)")
-            print(array[2])
-            return
-          }
-          print("- sig failed - which is OK - we may have more matching KIDS --")
+    for case let elem: Dictionary in trust {
+      if
+        kid == Data(hexString: elem["kid"] as! String)?.uint,
+        let x = (elem["coord"] as? Array<Any>)?[0] as? String,
+        let y = (elem["coord"] as? Array<Any>)?[1] as? String
+      {
+        print("We know this KID - check if this sig works...")
+        if COSE.verify(cbor, with: x, and: y) {
+          print("All is well! Payload: ", payload)
+          return
         }
-        print("Nope - all failed - sadness all around")
-        assert(false)
+        print("- sig failed - which is OK - we may have more matching KIDS --")
       }
     }
+    print("Nope - all failed - sadness all around")
+    XCTAssert(false)
   }
 }
 
@@ -147,8 +102,6 @@ class EHNTests: XCTestCase {
 
  Produces:
 
- All is WELL !
- Payload (decoded)
- byteString([161, 99, 102, 111, 111, 99, 98, 97, 114])
- 
+ All is well! Payload:  map([SwiftCBOR.CBOR.utf8String("foo"): SwiftCBOR.CBOR.utf8String("bar")])
+
  */