From 4de805dd37becf804ac82ab603fa1e67894c20c5 Mon Sep 17 00:00:00 2001
From: Max Goedjen <max.goedjen@gmail.com>
Date: Sun, 17 Jan 2021 16:16:38 -0800
Subject: [PATCH] Add support for SHA256 fingerprints (#198)

* Add SHA256

* Update tests

* Fix padding
---
 SecretKit/Common/OpenSSH/OpenSSHKeyWriter.swift | 10 +++++++++-
 SecretKitTests/OpenSSHWriterTests.swift         | 16 ++++++++++++----
 Secretive/Views/SecretDetailView.swift          |  5 ++++-
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/SecretKit/Common/OpenSSH/OpenSSHKeyWriter.swift b/SecretKit/Common/OpenSSH/OpenSSHKeyWriter.swift
index 9889835..a577476 100644
--- a/SecretKit/Common/OpenSSH/OpenSSHKeyWriter.swift
+++ b/SecretKit/Common/OpenSSH/OpenSSHKeyWriter.swift
@@ -19,7 +19,15 @@ public struct OpenSSHKeyWriter {
             .joined(separator: " ")
     }
 
-    public func openSSHFingerprint<SecretType: Secret>(secret: SecretType) -> String {
+    public func openSSHSHA256Fingerprint<SecretType: Secret>(secret: SecretType) -> String {
+        // OpenSSL format seems to strip the padding at the end.
+        let base64 = Data(SHA256.hash(data: data(secret: secret))).base64EncodedString()
+        let paddingRange = base64.index(base64.endIndex, offsetBy: -2)..<base64.endIndex
+        let cleaned = base64.replacingOccurrences(of: "=", with: "", range: paddingRange)
+        return "SHA256:\(cleaned)"
+    }
+
+    public func openSSHMD5Fingerprint<SecretType: Secret>(secret: SecretType) -> String {
         Insecure.MD5.hash(data: data(secret: secret))
             .compactMap { ("0" + String($0, radix: 16, uppercase: false)).suffix(2) }
             .joined(separator: ":")
diff --git a/SecretKitTests/OpenSSHWriterTests.swift b/SecretKitTests/OpenSSHWriterTests.swift
index d7a17b5..fcb0c96 100644
--- a/SecretKitTests/OpenSSHWriterTests.swift
+++ b/SecretKitTests/OpenSSHWriterTests.swift
@@ -6,8 +6,12 @@ class OpenSSHWriterTests: XCTestCase {
 
     let writer = OpenSSHKeyWriter()
 
-    func testECDSA256Fingerprint() {
-        XCTAssertEqual(writer.openSSHFingerprint(secret:  Constants.ecdsa256Secret), "dc:60:4d:ff:c2:d9:18:8b:2f:24:40:b5:7f:43:47:e5")
+    func testECDSA256MD5Fingerprint() {
+        XCTAssertEqual(writer.openSSHMD5Fingerprint(secret:  Constants.ecdsa256Secret), "dc:60:4d:ff:c2:d9:18:8b:2f:24:40:b5:7f:43:47:e5")
+    }
+
+    func testECDSA256SHA256Fingerprint() {
+        XCTAssertEqual(writer.openSSHSHA256Fingerprint(secret:  Constants.ecdsa256Secret), "SHA256:/VQFeGyM8qKA8rB6WGMuZZxZLJln2UgXLk3F0uTF650")
     }
 
     func testECDSA256PublicKey() {
@@ -19,8 +23,12 @@ class OpenSSHWriterTests: XCTestCase {
     XCTAssertEqual(writer.data(secret: Constants.ecdsa256Secret), Data(base64Encoded: "AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBOVEjgAA5PHqRgwykjN5qM21uWCHFSY/Sqo5gkHAkn+e1MMQKHOLga7ucB9b3mif33MBid59GRK9GEPVlMiSQwo="))
     }
 
-    func testECDSA384Fingerprint() {
-        XCTAssertEqual(writer.openSSHFingerprint(secret:  Constants.ecdsa384Secret), "66:e0:66:d7:41:ed:19:8e:e2:20:df:ce:ac:7e:2b:6e")
+    func testECDSA384MD5Fingerprint() {
+        XCTAssertEqual(writer.openSSHMD5Fingerprint(secret:  Constants.ecdsa384Secret), "66:e0:66:d7:41:ed:19:8e:e2:20:df:ce:ac:7e:2b:6e")
+    }
+
+    func testECDSA384SHA256Fingerprint() {
+        XCTAssertEqual(writer.openSSHSHA256Fingerprint(secret:  Constants.ecdsa384Secret), "SHA256:GJUEymQNL9ymaMRRJCMGY4rWIJHu/Lm8Yhao/PAiz1I")
     }
 
     func testECDSA384PublicKey() {
diff --git a/Secretive/Views/SecretDetailView.swift b/Secretive/Views/SecretDetailView.swift
index e1878dd..20fa76e 100644
--- a/Secretive/Views/SecretDetailView.swift
+++ b/Secretive/Views/SecretDetailView.swift
@@ -10,7 +10,10 @@ struct SecretDetailView<SecretType: Secret>: View {
     var body: some View {
         Form {
             Section {
-                CopyableView(title: "Fingerprint", image: Image(systemName: "touchid"), text: keyWriter.openSSHFingerprint(secret: secret))
+                CopyableView(title: "SHA256 Fingerprint", image: Image(systemName: "touchid"), text: keyWriter.openSSHSHA256Fingerprint(secret: secret))
+                Spacer()
+                    .frame(height: 20)
+                CopyableView(title: "MD5 Fingerprint", image: Image(systemName: "touchid"), text: keyWriter.openSSHMD5Fingerprint(secret: secret))
                 Spacer()
                     .frame(height: 20)
                 CopyableView(title: "Public Key", image: Image(systemName: "key"), text: keyString)