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December 12, 2014 15:02
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AES String Encryption (CBC) Example Code for C#
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using System; | |
using System.Collections.Generic; | |
using System.Linq; | |
using System.Security.Cryptography; | |
using System.Text; | |
using System.Threading.Tasks; | |
namespace aes_example | |
{ | |
using System; | |
using System.IO; | |
using System.Security.Cryptography; | |
class Program | |
{ | |
public static void Main() | |
{ | |
try | |
{ | |
string original = "Here is some data to encrypt!"; | |
// Create a new instance of the Aes | |
// class. This generates a new key and initialization | |
// vector (IV). | |
using (var random = new RNGCryptoServiceProvider()) | |
{ | |
var key = new byte[16]; | |
random.GetBytes(key); | |
// Encrypt the string to an array of bytes. | |
byte[] encrypted = EncryptStringToBytes_Aes(original, key); | |
// Decrypt the bytes to a string. | |
string roundtrip = DecryptStringFromBytes_Aes(encrypted, key); | |
//Display the original data and the decrypted data. | |
Console.WriteLine("Original: {0}", original); | |
Console.WriteLine("Encrypted (b64-encode): {0}", Convert.ToBase64String(encrypted)); | |
Console.WriteLine("Round Trip: {0}", roundtrip); | |
Console.ReadKey(); | |
} | |
} | |
catch (Exception e) | |
{ | |
Console.WriteLine("Error: {0}", e.Message); | |
} | |
} | |
static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key) | |
{ | |
byte[] encrypted; | |
byte[] IV; | |
using (Aes aesAlg = Aes.Create()) | |
{ | |
aesAlg.Key = Key; | |
aesAlg.GenerateIV(); | |
IV = aesAlg.IV; | |
aesAlg.Mode = CipherMode.CBC; | |
var encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV); | |
// Create the streams used for encryption. | |
using (var msEncrypt = new MemoryStream()) | |
{ | |
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)) | |
{ | |
using (var swEncrypt = new StreamWriter(csEncrypt)) | |
{ | |
//Write all data to the stream. | |
swEncrypt.Write(plainText); | |
} | |
encrypted = msEncrypt.ToArray(); | |
} | |
} | |
} | |
var combinedIvCt = new byte[IV.Length + encrypted.Length]; | |
Array.Copy(IV, 0, combinedIvCt, 0, IV.Length); | |
Array.Copy(encrypted, 0, combinedIvCt, IV.Length, encrypted.Length); | |
// Return the encrypted bytes from the memory stream. | |
return combinedIvCt; | |
} | |
static string DecryptStringFromBytes_Aes(byte[] cipherTextCombined, byte[] Key) | |
{ | |
// Declare the string used to hold | |
// the decrypted text. | |
string plaintext = null; | |
// Create an Aes object | |
// with the specified key and IV. | |
using (Aes aesAlg = Aes.Create()) | |
{ | |
aesAlg.Key = Key; | |
byte[] IV = new byte[aesAlg.BlockSize/8]; | |
byte[] cipherText = new byte[cipherTextCombined.Length - IV.Length]; | |
Array.Copy(cipherTextCombined, IV, IV.Length); | |
Array.Copy(cipherTextCombined, IV.Length, cipherText, 0, cipherText.Length); | |
aesAlg.IV = IV; | |
aesAlg.Mode = CipherMode.CBC; | |
// Create a decrytor to perform the stream transform. | |
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV); | |
// Create the streams used for decryption. | |
using (var msDecrypt = new MemoryStream(cipherText)) | |
{ | |
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)) | |
{ | |
using (var srDecrypt = new StreamReader(csDecrypt)) | |
{ | |
// Read the decrypted bytes from the decrypting stream | |
// and place them in a string. | |
plaintext = srDecrypt.ReadToEnd(); | |
} | |
} | |
} | |
} | |
return plaintext; | |
} | |
} | |
} |
Are you the original writer of this code?
https://docs.microsoft.com/en-us/dotnet/api/system.security.cryptography.aes?view=netframework-4.8
@kelalaka-153 No, I did not write this code. The fine folks at Microsoft did, but I’m guessing that you may already know that since you pasted a link to their site in your original comment. 😄
I copied this code into a snippet to make it easier for me to find and reference without having to search for it again.
No, I don't know. Usually, I put a link on top of the class, function.
Thanks man, awesome code!
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@jipsonsds, In this example, the text is encrypted and not the file