SystemExtensions Security

SystemExtensions.NetStandard.Security/Hashing/IHashingService.cs

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+using System.IO;
+using System.Threading.Tasks;
+
+namespace SystemExtensions.NetStandard.Security.Hashing
+{
+    public interface IHashingService
+    {
+        Task<string> Hash(string raw);
+        Task<byte[]> Hash(byte[] raw);
+        Task<Stream> Hash(Stream raw);
+    }
+}

SystemExtensions.NetStandard.Security/Hashing/Sha256HashingService.cs

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+using System;
+using System.IO;
+using System.Security.Cryptography;
+using System.Threading.Tasks;
+
+namespace SystemExtensions.NetStandard.Security.Hashing
+{
+    public sealed class Sha256HashingService : IHashingService
+    {
+        public async Task<string> Hash(string raw)
+        {
+            using var rawStream = BytesToStream(StringToBytes(raw));
+            using var hashedStream = await HashInternal(rawStream).ConfigureAwait(false);
+            return StreamToString(hashedStream);
+        }
+        public async Task<byte[]> Hash(byte[] raw)
+        {
+            using var rawStream = BytesToStream(raw);
+            using var hashedStream = await HashInternal(rawStream).ConfigureAwait(false);
+            return StreamToBytes(hashedStream);
+        }
+        public async Task<Stream> Hash(Stream raw)
+        {
+            return await HashInternal(raw);
+        }
+
+        private static byte[] StreamToBytes(Stream value)
+        {
+            value.Position = 0;
+            byte[] buffer = new byte[1024];
+            using var ms = new MemoryStream();
+            int read = -1;
+            do
+            {
+                read = value.Read(buffer, 0, buffer.Length);
+                ms.Write(buffer, 0, read);
+            } while (read > 0);
+            return ms.ToArray();
+        }
+        private static string StreamToString(Stream value)
+        {
+            return Convert.ToBase64String(StreamToBytes(value));
+        }
+        private static byte[] StringToBytes(string value)
+        {
+            return Convert.FromBase64String(value);
+        }
+        private static Stream BytesToStream(byte[] value)
+        {
+            return new MemoryStream(value);
+        }
+        private static async Task<Stream> HashInternal(Stream raw)
+        {
+            if (raw is null) throw new ArgumentNullException(nameof(raw));
+
+            using var sha256 = SHA256.Create();
+            return await Task.Run(() => new MemoryStream(sha256.ComputeHash(raw)));
+        }
+    }
+}