Sample Program to Convert String to Hex and Hex to String in CSharp (C#)

Here is the sample program to convert String to Hex and Hex to String in CSharp (C#).

String to Hex:

public static string ConvertStringToHex(String input, System.Text.Encoding encoding)
{
    Byte[] stringBytes = encoding.GetBytes(input);
    StringBuilder sbBytes = new StringBuilder(stringBytes.Length * 2);
 
    foreach (byte b in stringBytes)
    {
        sbBytes.AppendFormat("{0:X2}", b);
    }
 
return sbBytes.ToString();
}

Hex to String:

public static string ConvertHexToString(String hexInput, System.Text.Encoding encoding)
{
    int numberChars = hexInput.Length;
    byte[] bytes = new byte[numberChars / 2];
 
    for (int i = 0; i < numberChars; i += 2)
    {
        bytes[i / 2] = Convert.ToByte(hexInput.Substring(i, 2), 16);
    }
 
    return encoding.GetString(bytes);
}

Sample Program to Encrypt and Decrypt string using RijndaelManaged in CSharp (C#)

Here is a class to Encrypt and Decrypt a given string using RijndaelManaged. You have to change the private variable value based on your strength requirement of the encryption.

Encryption:

public static string Encrypt(string plainText)
{
    byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
    byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
    byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
    PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations);
    byte[] keyBytes = password.GetBytes(keySize / 8);
    RijndaelManaged symmetricKey = new RijndaelManaged();
    symmetricKey.Mode = CipherMode.CBC;
    ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
    MemoryStream memoryStream = new MemoryStream();
    CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
    cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
    cryptoStream.FlushFinalBlock();
    byte[] cipherTextBytes = memoryStream.ToArray();
    memoryStream.Close();
    cryptoStream.Close();
    string cipherText = Convert.ToBase64String(cipherTextBytes);
    return cipherText;
 }

Decryption:

public static string Decrypt(string cipherText)
{
    byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
    byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
    byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
    PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations);
    byte[] keyBytes = password.GetBytes(keySize / 8);
    RijndaelManaged symmetricKey = new RijndaelManaged();
    symmetricKey.Mode = CipherMode.CBC;
    ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
    MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
    CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
    byte[] plainTextBytes = new byte[cipherTextBytes.Length];
    int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
    memoryStream.Close();
    cryptoStream.Close();
    string plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
    return plainText;
 }

These private variables also needs to be initialized within the same class.

    private const string passPhrase = "Pas5pr@se";
    private const string saltValue = "s@1tValue";
    private const string hashAlgorithm = "MD5";
    private const int passwordIterations = 2;
    private const string initVector = "@1B2c3D4e5F6g7H8";
    private const int keySize = 256;

HttpContext.Current is null in Wcf Service

Issue:

HttpContext.Current is null in wcf service

Solution:

Set the aspNetCompatibilityEnabled is true in the Web.Config file

<system.serviceModel>
     <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
</system.serviceModel>

(Solved) Error: Memory gates checking failed because the free memory (203841536 bytes) is less than 5% of total memory. As a result, the service will not be available for incoming requests. To resolve this, either reduce the load on the machine or adjust the value of minFreeMemoryPercentageToActivateService on the serviceHostingEnvironment config element.

Error: 

Memory gates checking failed because the free memory (203841536 bytes) is less than 5% of total memory. As a result, the service will not be available for incoming requests. To resolve this, either reduce the load on the machine or adjust the value of minFreeMemoryPercentageToActivateService on the serviceHostingEnvironment config element.

Solution:

• To resolve this, either reduce the load on the machine or adjust the value of minFreeMemoryPercentageToActivateService on the serviceHostingEnvironment config element.

<system.serviceModel>
    <serviceHostingEnvironment minFreeMemoryPercentageToActivateService="0" />
</system.serviceModel>

(Solved) Error: You do not have permission to view this directory or page using the credentials you supplied (access denied due to Access Control Lists). Ask the Web server's administrator to give you access to 'C:\inetpub\wwwroot\...\Service.svc

Error:

You do not have permission to view this directory or page using the credentials you supplied (access denied due to Access Control Lists). Ask the Web server's administrator to give you access to 'C:\inetpub\wwwroot\...\Service.svc

Solution:

• Give access permission to the "IUSR" in IIS. That should solved the problem.