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How to encrypt string in c#?

I want to store a value in the registry but I want it to be encrypted. How do I do this? I also need to be able to decrypt it. I'm using C#.

Rikin Shah

Hi Pdering,

A simple example would be better to make encryption-decryption understand:
http://www.codeproject.com/Articles/14150/Encrypt-and-Decrypt-Data-with-C

Regards,
Rikin.

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kaufmed

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Member_2_99151

Hi,

I always use the code here to do any simple text encryption...

http://www.dijksterhuis.org/encrypting-decrypting-string/

James

Naman Goel

Here is an example using RSA. Replace your_rsa_key with your RSA key.

var provider = new System.Security.Cryptography.RSACryptoServiceProvider();
provider.ImportParameters(your_rsa_key);

var encryptedBytes = provider.Encrypt(
    System.Text.Encoding.UTF8.GetBytes("Hello World!"), true);

string decryptedTest = System.Text.Encoding.UTF8.GetString(
    provider.Decrypt(encryptedBytes, true));

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For more info, visit MSDN - RSACryptoServiceProvider

Naman Goel

also you can leverage on System.Security.Cryptography Namespace

http://msdn.microsoft.com/en-us/library/system.security.cryptography.aspx

jonnidip

I use these 2 extension methods:

    public static class ExtensionMethods_String
    {
        /// <summary>
        /// Encrypts a string using the supplied key. Encoding is done using RSA encryption.
        /// </summary>
        /// <param name="stringToEncrypt">String that must be encrypted.</param>
        /// <param name="key">Encryptionkey.</param>
        /// <param name="encoding">Text Encoding</param>
        /// <returns>A string representing a Byte array separated by a minus sign.</returns>
        /// <exception cref="ArgumentException">Occurs when stringToEncrypt or key is null or empty.</exception>
        public static String Encrypt(this String stringToEncrypt, String key, Encoding encoding)
        {
            if (String.IsNullOrEmpty(stringToEncrypt))
                throw new ArgumentException("An empty string value cannot be encrypted.");

            if (String.IsNullOrEmpty(key))
                throw new ArgumentException("Cannot encrypt using an empty key. Please supply an encryption key.");

            CspParameters cspp = new CspParameters();
            cspp.KeyContainerName = key;

            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspp);
            rsa.PersistKeyInCsp = true;

            Byte[] Bytes = rsa.Encrypt(encoding.GetBytes(stringToEncrypt), true);

            return BitConverter.ToString(Bytes);
        }

        /// <summary>
        /// Decrypts a string using the supplied key. Decoding is done using RSA encryption.
        /// </summary>
        /// <param name="stringToDecrypt">String that must be decrypted.</param>
        /// <param name="key">Decryptionkey.</param>
        /// <param name="encoding">Text Encoding</param>
        /// <returns>The decrypted string or null if decryption failed.</returns>
        /// <exception cref="ArgumentException">Occurs when stringToDecrypt or key is null or empty.</exception>
        public static String Decrypt(this String stringToDecrypt, String key, Encoding encoding)
        {
            String result = null;

            if (String.IsNullOrEmpty(stringToDecrypt))
                throw new ArgumentException("An empty string value cannot be encrypted.");

            if (String.IsNullOrEmpty(key))
                throw new ArgumentException("Cannot decrypt using an empty key. Please supply a decryption key.");

            try
            {
                CspParameters cspp = new CspParameters();
                cspp.KeyContainerName = key;

                RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspp);
                rsa.PersistKeyInCsp = true;

                String[] decryptArray = stringToDecrypt.Split(new String[] { "-" }, StringSplitOptions.None);
                Byte[] decryptByteArray = Array.ConvertAll<String, Byte>(decryptArray, (s => Convert.ToByte(Byte.Parse(s, System.Globalization.NumberStyles.HexNumber))));


                Byte[] Bytes = rsa.Decrypt(decryptByteArray, true);

                result = encoding.GetString(Bytes);
            }
            finally
            {
                // no need for further processing
            }

            return result;
        }
   }

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The usage is as simple as:

String EncryptedString = MyString.Encrypt(MyKey, Encoding.UTF8);
String DecryptedString = EncryptedString.Decrypt(MyKey, Encoding.UTF8)

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Hope this helps.
Regards.