davidmtamas · April 2, 2020 07:16 · Apr 2, 2020
diff --git a/CryptoKitExample.swift b/CryptoKitExample.swift
@@ -0,0 +1,27 @@
+import CryptoSwift
+import CommonCrypto
+
+#if canImport(CryptoKit)
+import CryptoKit
+#endif
+
+public final class PublicKeyPinner {
+  ...
+  /// Creates a hash from the received data using the `sha256` algorithm.
+  /// `Returns` the `base64` encoded representation of the hash.
+  ///
+  /// To replicate the output of the `openssl dgst -sha256` command, an array of specific bytes need to be appended to
+  /// the beginning of the data to be hashed.
+  /// - Parameter data: The data to be hashed.
+  private func hash(data: Data) -> String {
+      // Add the missing ASN1 header for public keys to re-create the subject public key info
+      var keyWithHeader = Data(rsa2048Asn1Header)
+      keyWithHeader.append(data)
+      // Check if iOS 13 is available, and use CryptoKit's hasher
+      if #available(iOS 13, *) {
+          return Data(SHA256.hash(data: keyWithHeader)).base64EncodedString()
+      } else {
+          ...
+      }
+  }
+}