HashFunctions.cs

Go to the documentation of this file.

// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
// 
//        http://www.apache.org/licenses/LICENSE-2.0
// 
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
//

using System;
using System.Security.Cryptography;

namespace Deveel.Data.Security {
    public static class HashFunctions {
        public static IHashFunction Sha1 {
            get { return new HashFunction("SHA1"); }
        }

        public static IHashFunction Sha256 {
            get { return new HashFunction("SHA256"); }
        }

        public static IHashFunction Sha384 {
            get { return new HashFunction("SHA384"); }
        }

        public static IHashFunction Sha512 {
            get { return new HashFunction("SHA512"); }
        }

        public static IHashFunction Md5 {
            get { return new HashFunction("MD5"); }
        }

        public static IKeyedHashFunction HmacSha256 {
            get { return new KeyedHashFunction("HMACSHA256"); }
        }

        public static IKeyedHashFunction HmacSha384 {
            get { return new KeyedHashFunction("HMACSHA384"); }
        }

        public static IKeyedHashFunction HmacSha512 {
            get { return new KeyedHashFunction("HMACSHA512"); }
        }

        public static IKeyedHashFunction HmacSha1 {
            get { return new KeyedHashFunction("HMACSHA1");}
        }

        public static IKeyedHashFunction HmacMd5 {
            get { return new KeyedHashFunction("HMACMD5"); }
        }

        public static IHashFunction GetFunction(string functionName) {
            if (String.Equals(functionName, "SHA256", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "SHA-256", StringComparison.OrdinalIgnoreCase))
                return Sha256;

            if (String.Equals(functionName, "SHA384", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "SHA-384", StringComparison.OrdinalIgnoreCase))
                return Sha384;

            if (String.Equals(functionName, "SHA512", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "SHA-512", StringComparison.OrdinalIgnoreCase))
                return Sha512;

            if (String.Equals(functionName, "MD5", StringComparison.OrdinalIgnoreCase))
                return Md5;

            if (String.Equals(functionName, "SHA1", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "SHA-1", StringComparison.OrdinalIgnoreCase))
                return Sha1;

            // HMAC
            if (String.Equals(functionName, "HMAC-SHA256", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMACSHA256", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMAC-SHA-256", StringComparison.OrdinalIgnoreCase))
                return HmacSha256;

            if (String.Equals(functionName, "HMAC-SHA384", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMACSHA384", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMAC-SHA-384", StringComparison.OrdinalIgnoreCase))
                return HmacSha384;

            if (String.Equals(functionName, "HMAC-SHA512", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMACSHA512", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMAC-SHA-512", StringComparison.OrdinalIgnoreCase))
                return HmacSha512;

            if (String.Equals(functionName, "HMAC-SHA1", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMACSHA1", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMAC-SHA-1", StringComparison.OrdinalIgnoreCase))
                return HmacSha1;

            if (String.Equals(functionName, "HMAC-MD5", StringComparison.OrdinalIgnoreCase) ||
                String.Equals(functionName, "HMACMD5", StringComparison.OrdinalIgnoreCase))
                return HmacMd5;

            return null;
        }

        #region HashFunction

        class HashFunction : IHashFunction {
            public HashFunction(string hashName) {
                Hash = HashAlgorithm.Create(hashName);

                if (Hash == null)
                    throw new ArgumentException(String.Format("Hash function {0} is not supported", hashName));
            }

            private HashAlgorithm Hash { get; set; }

            public void Dispose() {
                Hash.Clear();
            }

            public int HashSize {
                get { return Hash.HashSize; }
            }

            public byte[] Compute(byte[] data) {
                return Hash.ComputeHash(data);
            }
        }

        #endregion

        #region KeyedHashFunction

        class KeyedHashFunction : IKeyedHashFunction {
            public KeyedHashFunction(string hashName) {
                Hash = KeyedHashAlgorithm.Create(hashName);

                if (Hash == null)
                    throw new ArgumentException(String.Format("The hash function {0} is not supported", hashName));
            }

            private KeyedHashAlgorithm Hash { get; set; }

            public void Dispose() {
                Hash.Clear();
            }

            public int HashSize {
                get { return Hash.HashSize; }
            }

            public byte[] Compute(byte[] data) {
                return Hash.ComputeHash(data);
            }

            public byte[] Key {
                get { return Hash.Key; }
                set { Hash.Key = value; }
            }
        }

        #endregion
    }
}