add Pilz.Cryptography

Pilz.Cryptography/SecureString.cs

@@ -0,0 +1,78 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Pilz.Cryptography
+{
+    public class SecureString
+    {
+        public static ICrypter DefaultCrypter { get; set; }
+
+        [JsonIgnore]
+        public ICrypter Crypter { get; set; }
+
+        [JsonProperty]
+        public string EncryptedValue { get; set; }
+
+        [JsonIgnore]
+        public string Value
+        {
+            get => GetCrypter().Decrypt(EncryptedValue);
+            set => EncryptedValue = GetCrypter().Encrypt(Value);
+        }
+
+        public SecureString() :
+            this(string.Empty, true)
+        {
+        }
+
+        public SecureString(string value, bool isEncrypted) :
+            this(value, isEncrypted, null)
+        {
+        }
+
+        public SecureString(string value, bool isEncrypted, ICrypter crypter)
+        {
+            Crypter = crypter;
+
+            if (isEncrypted)
+                EncryptedValue = value;
+            else
+                Value = value;
+        }
+
+        private ICrypter GetCrypter()
+        {
+            if (Crypter == null)
+            {
+                if (DefaultCrypter == null)
+                    DefaultCrypter = new SimpleStringCrypter(string.Empty);
+                Crypter = DefaultCrypter;
+            }
+            return Crypter;
+        }
+
+        public override string ToString() => Value;
+
+        public override bool Equals(object obj)
+        {
+            var @string = obj as SecureString;
+            return @string != null &&
+                   EncryptedValue == @string.EncryptedValue;
+        }
+
+        public override int GetHashCode()
+        {
+            return -2303024 + EqualityComparer<string>.Default.GetHashCode(EncryptedValue);
+        }
+
+        public static implicit operator string(SecureString value) => value.Value;
+        public static implicit operator SecureString(string value) => new SecureString(value, false);
+
+        public static bool operator ==(SecureString left, SecureString right) => left.EncryptedValue == right.EncryptedValue;
+        public static bool operator !=(SecureString left, SecureString right) => left.EncryptedValue != right.EncryptedValue;
+    }
+}