How to Encrypt and Decrypt

Hey Jaya Prakash, can you please provide sample of your json data ?

@Amit Not Working sir,

throwing exception the input data is not a complete block.

Try this

using System;
using System.Security.Cryptography;
using System.Text;
using Newtonsoft.Json;

public class Program
{
    public static void Main()
    {
        // Sample JSON object
        var jsonObject = new
        {
            Name = "Amit",
            Age = 35,
            Address = "Hyderabad"
        };

        // Generate a random 256-bit encryption key and a 128-bit initialization vector (IV)
        byte[] key = new byte[32];
        using (var rng = new RNGCryptoServiceProvider())
        {
            rng.GetBytes(key);
        }
        byte[] iv = new byte[16];
        using (var rng = new RNGCryptoServiceProvider())
        {
            rng.GetBytes(iv);
        }

        // Convert the JSON object to a string and encode it in UTF-8 format
        string jsonString = JsonConvert.SerializeObject(jsonObject);
        byte[] jsonBytes = Encoding.UTF8.GetBytes(jsonString);

        // Encrypt the JSON bytes using the AES cipher with CBC mode and PKCS5 padding
        byte[] encryptedBytes;
        using (Aes aes = Aes.Create())
        {
            aes.Key = key;
            aes.IV = iv;
            aes.Mode = CipherMode.CBC;
            aes.Padding = PaddingMode.PKCS7;

            using (var encryptor = aes.CreateEncryptor())
            {
                encryptedBytes = encryptor.TransformFinalBlock(jsonBytes, 0, jsonBytes.Length);
            }
        }
        string encryptedString = Encoding.UTF8.GetString(encryptedBytes);

        // Decrypt the encrypted bytes using the same AES cipher with CBC mode and PKCS5 padding
        byte[] decryptedBytes;
        using (Aes aes = Aes.Create())
        {
            aes.Key = key;
            aes.IV = iv;
            aes.Mode = CipherMode.CBC;
            aes.Padding = PaddingMode.PKCS7;

            using (var decryptor = aes.CreateDecryptor())
            {
                decryptedBytes = decryptor.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length);
            }
        }

        // Convert the decrypted bytes back to a JSON object
        string decryptedString = Encoding.UTF8.GetString(decryptedBytes);
        var decryptedJsonObject = JsonConvert.DeserializeObject(decryptedString);

        // Print the original and decrypted JSON objects
        Console.WriteLine("Original JSON object: " + jsonString);
        Console.WriteLine("Encrypted JSON object: " + encryptedString);
        Console.WriteLine("Decrypted JSON object: " + decryptedString);
    }
}

@Rajkiran Swain sir,

Pls provide code  also for Decryption thank you.

Sure, I can help you with that. Here's an example code snippet in C# that uses the built-in System.Security.Cryptography library to encrypt a JSON object using AES-256 with CBC mode and PKCS5 padding in ASP.NET:

using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
using Newtonsoft.Json;

// Define the JSON object to encrypt
var data = new {
    name = "John Doe",
    age = 30,
    email = "[email protected]"
};

// Convert the JSON object to a string
var json_data = JsonConvert.SerializeObject(data);

// Define the encryption key and initialization vector (IV)
var key = Encoding.UTF8.GetBytes("secretkey1234567"); // 16-byte key for AES-256
var iv = Encoding.UTF8.GetBytes("initialvector123"); // 16-byte IV for CBC mode

// Create a new AES cipher with CBC mode and PKCS5 padding
var aes = Aes.Create();
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
aes.KeySize = 256;
aes.BlockSize = 128;
aes.Key = key;
aes.IV = iv;

// Convert the data to a byte array
var json_bytes = Encoding.UTF8.GetBytes(json_data);

// Pad the data to a multiple of 16 bytes using PKCS5 padding
var block_size = aes.BlockSize / 8;
var padding = block_size - (json_bytes.Length % block_size);
var padded_data = new byte[json_bytes.Length + padding];
Array.Copy(json_bytes, padded_data, json_bytes.Length);
for (int i = json_bytes.Length; i < padded_data.Length; i++) {
    padded_data[i] = (byte)padding;
}

// Encrypt the padded data using the AES cipher
var encryptor = aes.CreateEncryptor();
var encrypted_data = encryptor.TransformFinalBlock(padded_data, 0, padded_data.Length);

// Convert the encrypted data to a base64-encoded string
var encrypted_string = Convert.ToBase64String(encrypted_data);