Crypt.cs

public class Crypt
    {

        public string SHA1(string input)
        {
            using (SHA1Managed sha1 = new SHA1Managed())
            {
                var hash = sha1.ComputeHash(Encoding.UTF8.GetBytes(input));
                var sb = new StringBuilder(hash.Length * 2);

                foreach (byte b in hash)
                {
                    sb.Append(b.ToString("x2"));
                }

                return sb.ToString();
            }
        }

        public string SHA256(string input)
        {
            using (SHA256Managed sha256 = new SHA256Managed())
            {
                var hash = sha256.ComputeHash(Encoding.UTF8.GetBytes(input));
                var sb = new StringBuilder();

                foreach (byte b in hash)
                {
                    sb.Append(b.ToString("x2"));
                }

                return sb.ToString();
            }
        }

        public string MD5(string input)
        {
            MD5CryptoServiceProvider m = new MD5CryptoServiceProvider();
            byte[] hash = m.ComputeHash(Encoding.UTF8.GetBytes(input));

            var sb = new StringBuilder(hash.Length * 2);

            foreach (byte b in hash)
            {
                sb.Append(b.ToString("x2"));
            }

            return sb.ToString();
        }

        public string Base64Encode(string plainText)
        {
            var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);
            return System.Convert.ToBase64String(plainTextBytes);
        }

        public string Base64Decode(string base64EncodedData)
        {
            var base64EncodedBytes = System.Convert.FromBase64String(base64EncodedData);
            return System.Text.Encoding.UTF8.GetString(base64EncodedBytes);
        }

        public byte[] EncryptDataOaepSha1(X509Certificate2 cert, byte[] data)
        {
            using (RSA rsa = cert.GetRSAPublicKey())
            {
                return rsa.Encrypt(data, RSAEncryptionPadding.OaepSHA1);
            }
        }

        public byte[] DecryptDataOaepSha1(X509Certificate2 cert, byte[] data)
        {
            using (RSA rsa = cert.GetRSAPrivateKey())
            {
                return rsa.Decrypt(data, RSAEncryptionPadding.OaepSHA1);
            }
        }

    }