Reputation: 205
I using this class to perform AES encryption/decryption:
class Aes
{
static byte[] Key = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f };
static byte[] IV = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
public static byte[] Encrypt(string plainText)
{
byte[] encrypted;
// Create a new AesManaged.
using (AesManaged aes = new AesManaged())
{
aes.Padding = PaddingMode.None;
aes.Mode = CipherMode.ECB;
// Create encryptor
ICryptoTransform encryptor = aes.CreateEncryptor(Key, IV);
// Create MemoryStream
using (MemoryStream ms = new MemoryStream())
{
// Create crypto stream using the CryptoStream class. This class is the key to encryption
// and encrypts and decrypts data from any given stream. In this case, we will pass a memory stream
// to encrypt
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
// Create StreamWriter and write data to a stream
using (StreamWriter sw = new StreamWriter(cs))
sw.Write(plainText);
encrypted = ms.ToArray();
}
}
}
// Return encrypted data
return encrypted;
}
public static string Decrypt(byte[] cipherText/*, byte[] Key=Key, byte[] IV=IV*/)
{
string plaintext = null;
// Create AesManaged
using (AesManaged aes = new AesManaged())
{
aes.Padding = PaddingMode.None;
aes.Mode = CipherMode.ECB;
// Create a decryptor
ICryptoTransform decryptor = aes.CreateDecryptor(Key, IV);
// Create the streams used for decryption.
using (MemoryStream ms = new MemoryStream(cipherText))
{
// Create crypto stream
using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
{
// Read crypto stream
using (StreamReader reader = new StreamReader(cs))
plaintext = reader.ReadToEnd();
}
}
}
return plaintext;
}
}
The problem is that when I encrypt using the following code I get the error: System.Security.Cryptography.CryptographicException: 'Length of the data to encrypt is invalid.'
var x = Aes.Encrypt(System.Text.Encoding.Default.GetString(new byte[] { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }));
Console.WriteLine(string.Join(", ", x.Select(b => b.ToString("X2"))));
I am trying to implement encrypted communication with a MSP432 microcontroller. According to this example, using these values:
Key: 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
Plaintext: 00112233445566778899aabbccddeeff
I should get:
Ciphertext: 8ea2b7ca516745bfeafc49904b496089
Can someone tell me what I am doing wrong?
Upvotes: 1
Views: 735
Reputation: 205
I managed to get it working using the following code:
public byte[] encryptdata(byte[] bytearraytoencrypt, string key, string iv)
{
AesCryptoServiceProvider dataencrypt = new AesCryptoServiceProvider();
//Block size : Gets or sets the block size, in bits, of the cryptographic operation.
dataencrypt.BlockSize = 128;
//KeySize: Gets or sets the size, in bits, of the secret key
dataencrypt.KeySize = 128;
//Key: Gets or sets the symmetric key that is used for encryption and decryption.
dataencrypt.Key = System.Text.Encoding.UTF8.GetBytes(key);
//IV : Gets or sets the initialization vector (IV) for the symmetric algorithm
dataencrypt.IV = System.Text.Encoding.UTF8.GetBytes(iv);
//Padding: Gets or sets the padding mode used in the symmetric algorithm
dataencrypt.Padding = PaddingMode.PKCS7;
//Mode: Gets or sets the mode for operation of the symmetric algorithm
dataencrypt.Mode = CipherMode.CBC;
//Creates a symmetric AES encryptor object using the current key and initialization vector (IV).
ICryptoTransform crypto1 = dataencrypt.CreateEncryptor(dataencrypt.Key, dataencrypt.IV);
//TransformFinalBlock is a special function for transforming the last block or a partial block in the stream.
//It returns a new array that contains the remaining transformed bytes. A new array is returned, because the amount of
//information returned at the end might be larger than a single block when padding is added.
byte[] encrypteddata = crypto1.TransformFinalBlock(bytearraytoencrypt, 0, bytearraytoencrypt.Length);
crypto1.Dispose();
//return the encrypted data
return encrypteddata;
}
//code to decrypt data
private byte[] decryptdata(byte[] bytearraytodecrypt, string key, string iv)
{
AesCryptoServiceProvider keydecrypt = new AesCryptoServiceProvider();
keydecrypt.BlockSize = 128;
keydecrypt.KeySize = 128;
keydecrypt.Key = System.Text.Encoding.UTF8.GetBytes(key);
keydecrypt.IV = System.Text.Encoding.UTF8.GetBytes(iv);
keydecrypt.Padding = PaddingMode.PKCS7;
keydecrypt.Mode = CipherMode.CBC;
ICryptoTransform crypto1 = keydecrypt.CreateDecryptor(keydecrypt.Key, keydecrypt.IV);
byte[] returnbytearray = crypto1.TransformFinalBlock(bytearraytodecrypt, 0, bytearraytodecrypt.Length);
crypto1.Dispose();
return returnbytearray;
}
Upvotes: 0