initial commit

Pulsar.Common/Cryptography/SafeComparison.cs

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+using System.Runtime.CompilerServices;
+
+namespace Pulsar.Common.Cryptography
+{
+    public class SafeComparison
+    {
+        /// <summary>
+        /// Compares two byte arrays for equality.
+        /// </summary>
+        /// <param name="a1">Byte array to compare</param>
+        /// <param name="a2">Byte array to compare</param>
+        /// <returns>True if equal, else false</returns>
+        /// <remarks>
+        /// Assumes that the byte arrays have the same length.
+        /// This method is safe against timing attacks.
+        /// </remarks>
+        [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
+        public static bool AreEqual(byte[] a1, byte[] a2)
+        {
+            bool result = true;
+            for (int i = 0; i < a1.Length; ++i)
+            {
+                if (a1[i] != a2[i])
+                    result = false;
+            }
+            return result;
+        }
+    }
+}