C#多种方式加密与解密示例（DES、SHA1、MD5）

/// <summary>
    /// SHA256加密，不可逆转
    /// </summary>
    /// <param name="str">string str:被加密的字符串</param>
    /// <returns>返回加密后的字符串</returns>
    private string SHA256Encrypt(string str)
    {
        System.Security.Cryptography.SHA256 s256 = new System.Security.Cryptography.SHA256Managed();
        byte[] byte1;
        byte1 = s256.ComputeHash(Encoding.Default.GetBytes(str));
        s256.Clear();
        return Convert.ToBase64String(byte1);
    }

    /// <summary>
    /// SHA384加密，不可逆转
    /// </summary>
    /// <param name="str">string str:被加密的字符串</param>
    /// <returns>返回加密后的字符串</returns>
    private string SHA384Encrypt(string str)
    {
        System.Security.Cryptography.SHA384 s384 = new System.Security.Cryptography.SHA384Managed();
        byte[] byte1;
        byte1 = s384.ComputeHash(Encoding.Default.GetBytes(str));
        s384.Clear();
        return Convert.ToBase64String(byte1);
    }

 

    /// <summary>
    /// SHA512加密，不可逆转
    /// </summary>
    /// <param name="str">string str:被加密的字符串</param>
    /// <returns>返回加密后的字符串</returns>
    private string SHA512Encrypt(string str)
    {
        System.Security.Cryptography.SHA512 s512 = new System.Security.Cryptography.SHA512Managed();
        byte[] byte1;
        byte1 = s512.ComputeHash(Encoding.Default.GetBytes(str));
        s512.Clear();
        return Convert.ToBase64String(byte1);
    }

 
    /// <summary>
    /// MD5加密，不可逆转
    /// </summary>
    /// <param name="str">string str:被加密的字符串</param>
    /// <returns>返回加密后的字符串</returns>
    private string MD5Encrypt(string str)
    {
        System.Security.Cryptography.MD5 m5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
        byte[] byte1;
        byte1 = m5.ComputeHash(Encoding.Default.GetBytes(str));
        m5.Clear();
        return Convert.ToBase64String(byte1);
    }