Added Tango.Serialization.

Added Tango.Settings.

1 files changed, 156 insertions, 0 deletions

diff --git a/Software/Visual_Studio/Tango.Serialization/CryptographyHelper.cs b/Software/Visual_Studio/Tango.Serialization/CryptographyHelper.cs
new file mode 100644
index 000000000..e072827fe
--- /dev/null
+++ b/Software/Visual_Studio/Tango.Serialization/CryptographyHelper.cs
@@ -0,0 +1,156 @@
+using System;
+using System.Text;
+using System.Security.Cryptography;
+using System.IO;
+using System.Linq;
+using System.Security;
+using System.Runtime.InteropServices;
+
+namespace Tango.Serialization
+{
+    /// <summary>
+    /// Represents a helper class for encryption and decryption of plain text.
+    /// </summary>
+    internal static class CryptographyHelper
+    {
+        private static SecureString passkey;
+
+        /// <summary>
+        /// Initializes the <see cref="CryptographyHelper"/> class.
+        /// </summary>
+        static CryptographyHelper()
+        {
+            passkey = new SecureString();
+            passkey.AppendChar('S');
+            passkey.AppendChar('@');
+            passkey.AppendChar('Y');
+            passkey.AppendChar('!');
+        }
+
+        // This constant is used to determine the keysize of the encryption algorithm in bits.
+        // We divide this by 8 within the code below to get the equivalent number of bytes.
+        private const int Keysize = 256;
+
+        // This constant determines the number of iterations for the password bytes generation function.
+        private const int DerivationIterations = 1000;
+
+        /// <summary>
+        /// Encrypts the specified plain text.
+        /// </summary>
+        /// <param name="plainText">The plain text.</param>
+        /// <returns></returns>
+        public static string Encrypt(string plainText)
+        {
+            // Salt and IV is randomly generated each time, but is preprended to encrypted cipher text
+            // so that the same Salt and IV values can be used when decrypting.  
+            var saltStringBytes = Generate256BitsOfRandomEntropy();
+            var ivStringBytes = Generate256BitsOfRandomEntropy();
+            var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
+            using (var password = new Rfc2898DeriveBytes(ConvertSecureStringToString(passkey), saltStringBytes, DerivationIterations))
+            {
+                var keyBytes = password.GetBytes(Keysize / 8);
+                using (var symmetricKey = new RijndaelManaged())
+                {
+                    symmetricKey.BlockSize = 256;
+                    symmetricKey.Mode = CipherMode.CBC;
+                    symmetricKey.Padding = PaddingMode.PKCS7;
+                    using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
+                    {
+                        using (var memoryStream = new MemoryStream())
+                        {
+                            using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
+                            {
+                                cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
+                                cryptoStream.FlushFinalBlock();
+                                // Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
+                                var cipherTextBytes = saltStringBytes;
+                                cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
+                                cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
+                                memoryStream.Close();
+                                cryptoStream.Close();
+                                return Convert.ToBase64String(cipherTextBytes);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Decrypts the specified cipher text.
+        /// </summary>
+        /// <param name="cipherText">The cipher text.</param>
+        /// <returns></returns>
+        public static string Decrypt(string cipherText)
+        {
+            // Get the complete stream of bytes that represent:
+            // [32 bytes of Salt] + [32 bytes of IV] + [n bytes of CipherText]
+            var cipherTextBytesWithSaltAndIv = Convert.FromBase64String(cipherText);
+            // Get the saltbytes by extracting the first 32 bytes from the supplied cipherText bytes.
+            var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
+            // Get the IV bytes by extracting the next 32 bytes from the supplied cipherText bytes.
+            var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
+            // Get the actual cipher text bytes by removing the first 64 bytes from the cipherText string.
+            var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();
+
+            using (var password = new Rfc2898DeriveBytes(ConvertSecureStringToString(passkey), saltStringBytes, DerivationIterations))
+            {
+                var keyBytes = password.GetBytes(Keysize / 8);
+                using (var symmetricKey = new RijndaelManaged())
+                {
+                    symmetricKey.BlockSize = 256;
+                    symmetricKey.Mode = CipherMode.CBC;
+                    symmetricKey.Padding = PaddingMode.PKCS7;
+                    using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
+                    {
+                        using (var memoryStream = new MemoryStream(cipherTextBytes))
+                        {
+                            using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
+                            {
+                                var plainTextBytes = new byte[cipherTextBytes.Length];
+                                var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
+                                memoryStream.Close();
+                                cryptoStream.Close();
+                                return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Generate256s the bits of random entropy.
+        /// </summary>
+        /// <returns></returns>
+        private static byte[] Generate256BitsOfRandomEntropy()
+        {
+            var randomBytes = new byte[32]; // 32 Bytes will give us 256 bits.
+            using (var rngCsp = new RNGCryptoServiceProvider())
+            {
+                // Fill the array with cryptographically secure random bytes.
+                rngCsp.GetBytes(randomBytes);
+            }
+            return randomBytes;
+        }
+
+        /// <summary>
+        /// Converts the secure string to string.
+        /// </summary>
+        /// <param name="value">The value.</param>
+        /// <returns></returns>
+        private static String ConvertSecureStringToString(SecureString value)
+        {
+            IntPtr valuePtr = IntPtr.Zero;
+            try
+            {
+                valuePtr = Marshal.SecureStringToGlobalAllocUnicode(value);
+                return Marshal.PtrToStringUni(valuePtr);
+            }
+            finally
+            {
+                Marshal.ZeroFreeGlobalAllocUnicode(valuePtr);
+            }
+        }
+    }
+}
\ No newline at end of file