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c# aes ctr no IV javascript [duplicate] - javascript

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I can't seem to find a nice clean example of using AES 128 bit encryption.
Does anyone have some sample code?

If you just want to use the built-in crypto provider RijndaelManaged, check out the following help article (it also has a simple code sample):
http://msdn.microsoft.com/en-us/library/system.security.cryptography.rijndaelmanaged.aspx
And just in case you need the sample in a hurry, here it is in all its plagiarized glory:
using System;
using System.IO;
using System.Security.Cryptography;
namespace RijndaelManaged_Example
{
class RijndaelExample
{
public static void Main()
{
try
{
string original = "Here is some data to encrypt!";
// Create a new instance of the RijndaelManaged
// class. This generates a new key and initialization
// vector (IV).
using (RijndaelManaged myRijndael = new RijndaelManaged())
{
myRijndael.GenerateKey();
myRijndael.GenerateIV();
// Encrypt the string to an array of bytes.
byte[] encrypted = EncryptStringToBytes(original, myRijndael.Key, myRijndael.IV);
// Decrypt the bytes to a string.
string roundtrip = DecryptStringFromBytes(encrypted, myRijndael.Key, myRijndael.IV);
//Display the original data and the decrypted data.
Console.WriteLine("Original: {0}", original);
Console.WriteLine("Round Trip: {0}", roundtrip);
}
}
catch (Exception e)
{
Console.WriteLine("Error: {0}", e.Message);
}
}
static byte[] EncryptStringToBytes(string plainText, byte[] Key, byte[] IV)
{
// Check arguments.
if (plainText == null || plainText.Length <= 0)
throw new ArgumentNullException("plainText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("IV");
byte[] encrypted;
// Create an RijndaelManaged object
// with the specified key and IV.
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
// Create a decryptor to perform the stream transform.
ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);
// Create the streams used for encryption.
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(plainText);
}
encrypted = msEncrypt.ToArray();
}
}
}
// Return the encrypted bytes from the memory stream.
return encrypted;
}
static string DecryptStringFromBytes(byte[] cipherText, byte[] Key, byte[] IV)
{
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
throw new ArgumentNullException("cipherText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("IV");
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
// Create an RijndaelManaged object
// with the specified key and IV.
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
// Create the streams used for decryption.
using (MemoryStream msDecrypt = new MemoryStream(cipherText))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
// Read the decrypted bytes from the decrypting stream
// and place them in a string.
plaintext = srDecrypt.ReadToEnd();
}
}
}
}
return plaintext;
}
}
}

I've recently had to bump up against this again in my own project - and wanted to share the somewhat simpler code that I've been using, as this question and series of answers kept coming up in my searches.
I'm not going to get into the security concerns around how often to update things like your Salt and Initialization Vector - that's a topic for a security forum, and there are some great resources out there to look at. This is simply a block of code to implement AesManaged in C#.
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
namespace Your.Namespace.Security {
public static class Cryptography {
#region Settings
private static int _iterations = 2;
private static int _keySize = 256;
private static string _hash = "SHA1";
private static string _salt = "aselrias38490a32"; // Random
private static string _vector = "8947az34awl34kjq"; // Random
#endregion
public static string Encrypt(string value, string password) {
return Encrypt<AesManaged>(value, password);
}
public static string Encrypt<T>(string value, string password)
where T : SymmetricAlgorithm, new() {
byte[] vectorBytes = GetBytes<ASCIIEncoding>(_vector);
byte[] saltBytes = GetBytes<ASCIIEncoding>(_salt);
byte[] valueBytes = GetBytes<UTF8Encoding>(value);
byte[] encrypted;
using (T cipher = new T()) {
PasswordDeriveBytes _passwordBytes =
new PasswordDeriveBytes(password, saltBytes, _hash, _iterations);
byte[] keyBytes = _passwordBytes.GetBytes(_keySize / 8);
cipher.Mode = CipherMode.CBC;
using (ICryptoTransform encryptor = cipher.CreateEncryptor(keyBytes, vectorBytes)) {
using (MemoryStream to = new MemoryStream()) {
using (CryptoStream writer = new CryptoStream(to, encryptor, CryptoStreamMode.Write)) {
writer.Write(valueBytes, 0, valueBytes.Length);
writer.FlushFinalBlock();
encrypted = to.ToArray();
}
}
}
cipher.Clear();
}
return Convert.ToBase64String(encrypted);
}
public static string Decrypt(string value, string password) {
return Decrypt<AesManaged>(value, password);
}
public static string Decrypt<T>(string value, string password) where T : SymmetricAlgorithm, new() {
byte[] vectorBytes = GetBytes<ASCIIEncoding>(_vector);
byte[] saltBytes = GetBytes<ASCIIEncoding>(_salt);
byte[] valueBytes = Convert.FromBase64String(value);
byte[] decrypted;
int decryptedByteCount = 0;
using (T cipher = new T()) {
PasswordDeriveBytes _passwordBytes = new PasswordDeriveBytes(password, saltBytes, _hash, _iterations);
byte[] keyBytes = _passwordBytes.GetBytes(_keySize / 8);
cipher.Mode = CipherMode.CBC;
try {
using (ICryptoTransform decryptor = cipher.CreateDecryptor(keyBytes, vectorBytes)) {
using (MemoryStream from = new MemoryStream(valueBytes)) {
using (CryptoStream reader = new CryptoStream(from, decryptor, CryptoStreamMode.Read)) {
decrypted = new byte[valueBytes.Length];
decryptedByteCount = reader.Read(decrypted, 0, decrypted.Length);
}
}
}
} catch (Exception ex) {
return String.Empty;
}
cipher.Clear();
}
return Encoding.UTF8.GetString(decrypted, 0, decryptedByteCount);
}
}
}
The code is very simple to use. It literally just requires the following:
string encrypted = Cryptography.Encrypt(data, "testpass");
string decrypted = Cryptography.Decrypt(encrypted, "testpass");
By default, the implementation uses AesManaged - but you could actually also insert any other SymmetricAlgorithm. A list of the available SymmetricAlgorithm inheritors for .NET 4.5 can be found at:
http://msdn.microsoft.com/en-us/library/system.security.cryptography.symmetricalgorithm.aspx
As of the time of this post, the current list includes:
AesManaged
RijndaelManaged
DESCryptoServiceProvider
RC2CryptoServiceProvider
TripleDESCryptoServiceProvider
To use RijndaelManaged with the code above, as an example, you would use:
string encrypted = Cryptography.Encrypt<RijndaelManaged>(dataToEncrypt, password);
string decrypted = Cryptography.Decrypt<RijndaelManaged>(encrypted, password);
I hope this is helpful to someone out there.

Look at sample in here..
http://msdn.microsoft.com/en-us/library/system.security.cryptography.rijndaelmanaged(v=VS.100).aspx#Y2262
The example on MSDN does not run normally (an error occurs) because there is no initial value of Initial Vector(iv) and Key. I add 2 line code and now work normally.
More details see below:
using System.Windows.Forms;
using System;
using System.Text;
using System.IO;
using System.Security.Cryptography;
namespace AES_TESTER
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
try
{
string original = "Here is some data to encrypt!";
MessageBox.Show("Original: " + original);
// Create a new instance of the RijndaelManaged
// class. This generates a new key and initialization
// vector (IV).
using (RijndaelManaged myRijndael = new RijndaelManaged())
{
myRijndael.GenerateKey();
myRijndael.GenerateIV();
// Encrypt the string to an array of bytes.
byte[] encrypted = EncryptStringToBytes(original, myRijndael.Key, myRijndael.IV);
StringBuilder s = new StringBuilder();
foreach (byte item in encrypted)
{
s.Append(item.ToString("X2") + " ");
}
MessageBox.Show("Encrypted: " + s);
// Decrypt the bytes to a string.
string decrypted = DecryptStringFromBytes(encrypted, myRijndael.Key, myRijndael.IV);
//Display the original data and the decrypted data.
MessageBox.Show("Decrypted: " + decrypted);
}
}
catch (Exception ex)
{
MessageBox.Show("Error: {0}", ex.Message);
}
}
static byte[] EncryptStringToBytes(string plainText, byte[] Key, byte[] IV)
{
// Check arguments.
if (plainText == null || plainText.Length <= 0)
throw new ArgumentNullException("plainText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("Key");
byte[] encrypted;
// Create an RijndaelManaged object
// with the specified key and IV.
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
rijAlg.Mode = CipherMode.CBC;
rijAlg.Padding = PaddingMode.Zeros;
// Create a decrytor to perform the stream transform.
ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);
// Create the streams used for encryption.
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(plainText);
}
encrypted = msEncrypt.ToArray();
}
}
}
// Return the encrypted bytes from the memory stream.
return encrypted;
}
static string DecryptStringFromBytes(byte[] cipherText, byte[] Key, byte[] IV)
{
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
throw new ArgumentNullException("cipherText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("Key");
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
// Create an RijndaelManaged object
// with the specified key and IV.
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
rijAlg.Mode = CipherMode.CBC;
rijAlg.Padding = PaddingMode.Zeros;
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
// Create the streams used for decryption.
using (MemoryStream msDecrypt = new MemoryStream(cipherText))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
// Read the decrypted bytes from the decrypting stream
// and place them in a string.
plaintext = srDecrypt.ReadToEnd();
}
}
}
}
return plaintext;
}
}
}

Using AES or implementing AES? To use AES, there is the System.Security.Cryptography.RijndaelManaged class.

For a more complete example that performs key derivation in addition to the AES encryption, see the answer and links posted in Getting AES encryption to work across Javascript and C#.
EDIT
a side note: Javascript Cryptography considered harmful. Worth the read.

//Code to encrypt Data :
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;
}

http://www.codeproject.com/Articles/769741/Csharp-AES-bits-Encryption-Library-with-Salt
using System.Security.Cryptography;
using System.IO;
 
public byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
{
byte[] encryptedBytes = null;
byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
using (var cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length);
cs.Close();
}
encryptedBytes = ms.ToArray();
}
}
return encryptedBytes;
}
public byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
{
byte[] decryptedBytes = null;
byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
using (var cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
cs.Close();
}
decryptedBytes = ms.ToArray();
}
}
return decryptedBytes;
}

Try this code, maybe useful.
1.Create New C# Project and add follows code to Form1:
using System;
using System.Windows.Forms;
using System.Security.Cryptography;
namespace ExampleCrypto
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
string strOriginalData = string.Empty;
string strEncryptedData = string.Empty;
string strDecryptedData = string.Empty;
strOriginalData = "this is original data 1234567890"; // your original data in here
MessageBox.Show("ORIGINAL DATA:\r\n" + strOriginalData);
clsCrypto aes = new clsCrypto();
aes.IV = "this is your IV"; // your IV
aes.KEY = "this is your KEY"; // your KEY
strEncryptedData = aes.Encrypt(strOriginalData, CipherMode.CBC); // your cipher mode
MessageBox.Show("ENCRYPTED DATA:\r\n" + strEncryptedData);
strDecryptedData = aes.Decrypt(strEncryptedData, CipherMode.CBC);
MessageBox.Show("DECRYPTED DATA:\r\n" + strDecryptedData);
}
}
}
2.Create clsCrypto.cs and copy paste follows code in your class and run your code. I used MD5 to generated Initial Vector(IV) and KEY of AES.
using System;
using System.Security.Cryptography;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Runtime.Remoting.Metadata.W3cXsd2001;
namespace ExampleCrypto
{
public class clsCrypto
{
private string _KEY = string.Empty;
protected internal string KEY
{
get
{
return _KEY;
}
set
{
if (!string.IsNullOrEmpty(value))
{
_KEY = value;
}
}
}
private string _IV = string.Empty;
protected internal string IV
{
get
{
return _IV;
}
set
{
if (!string.IsNullOrEmpty(value))
{
_IV = value;
}
}
}
private string CalcMD5(string strInput)
{
string strOutput = string.Empty;
if (!string.IsNullOrEmpty(strInput))
{
try
{
StringBuilder strHex = new StringBuilder();
using (MD5 md5 = MD5.Create())
{
byte[] bytArText = Encoding.Default.GetBytes(strInput);
byte[] bytArHash = md5.ComputeHash(bytArText);
for (int i = 0; i < bytArHash.Length; i++)
{
strHex.Append(bytArHash[i].ToString("X2"));
}
strOutput = strHex.ToString();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
return strOutput;
}
private byte[] GetBytesFromHexString(string strInput)
{
byte[] bytArOutput = new byte[] { };
if ((!string.IsNullOrEmpty(strInput)) && strInput.Length % 2 == 0)
{
SoapHexBinary hexBinary = null;
try
{
hexBinary = SoapHexBinary.Parse(strInput);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
bytArOutput = hexBinary.Value;
}
return bytArOutput;
}
private byte[] GenerateIV()
{
byte[] bytArOutput = new byte[] { };
try
{
string strIV = CalcMD5(IV);
bytArOutput = GetBytesFromHexString(strIV);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
return bytArOutput;
}
private byte[] GenerateKey()
{
byte[] bytArOutput = new byte[] { };
try
{
string strKey = CalcMD5(KEY);
bytArOutput = GetBytesFromHexString(strKey);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
return bytArOutput;
}
protected internal string Encrypt(string strInput, CipherMode cipherMode)
{
string strOutput = string.Empty;
if (!string.IsNullOrEmpty(strInput))
{
try
{
byte[] bytePlainText = Encoding.Default.GetBytes(strInput);
using (RijndaelManaged rijManaged = new RijndaelManaged())
{
rijManaged.Mode = cipherMode;
rijManaged.BlockSize = 128;
rijManaged.KeySize = 128;
rijManaged.IV = GenerateIV();
rijManaged.Key = GenerateKey();
rijManaged.Padding = PaddingMode.Zeros;
ICryptoTransform icpoTransform = rijManaged.CreateEncryptor(rijManaged.Key, rijManaged.IV);
using (MemoryStream memStream = new MemoryStream())
{
using (CryptoStream cpoStream = new CryptoStream(memStream, icpoTransform, CryptoStreamMode.Write))
{
cpoStream.Write(bytePlainText, 0, bytePlainText.Length);
cpoStream.FlushFinalBlock();
}
strOutput = Encoding.Default.GetString(memStream.ToArray());
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
return strOutput;
}
protected internal string Decrypt(string strInput, CipherMode cipherMode)
{
string strOutput = string.Empty;
if (!string.IsNullOrEmpty(strInput))
{
try
{
byte[] byteCipherText = Encoding.Default.GetBytes(strInput);
byte[] byteBuffer = new byte[strInput.Length];
using (RijndaelManaged rijManaged = new RijndaelManaged())
{
rijManaged.Mode = cipherMode;
rijManaged.BlockSize = 128;
rijManaged.KeySize = 128;
rijManaged.IV = GenerateIV();
rijManaged.Key = GenerateKey();
rijManaged.Padding = PaddingMode.Zeros;
ICryptoTransform icpoTransform = rijManaged.CreateDecryptor(rijManaged.Key, rijManaged.IV);
using (MemoryStream memStream = new MemoryStream(byteCipherText))
{
using (CryptoStream cpoStream = new CryptoStream(memStream, icpoTransform, CryptoStreamMode.Read))
{
cpoStream.Read(byteBuffer, 0, byteBuffer.Length);
}
strOutput = Encoding.Default.GetString(byteBuffer);
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
return strOutput;
}
}
}

You can use password from text box like key...
With this code you can encrypt/decrypt text, picture, word document, pdf....
public class Rijndael
{
private byte[] key;
private readonly byte[] vector = { 255, 64, 191, 111, 23, 3, 113, 119, 231, 121, 252, 112, 79, 32, 114, 156 };
ICryptoTransform EnkValue, DekValue;
public Rijndael(byte[] key)
{
this.key = key;
RijndaelManaged rm = new RijndaelManaged();
rm.Padding = PaddingMode.PKCS7;
EnkValue = rm.CreateEncryptor(key, vector);
DekValue = rm.CreateDecryptor(key, vector);
}
public byte[] Encrypt(byte[] byte)
{
byte[] enkByte= byte;
byte[] enkNewByte;
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, EnkValue, CryptoStreamMode.Write))
{
cs.Write(enkByte, 0, enkByte.Length);
cs.FlushFinalBlock();
ms.Position = 0;
enkNewByte= new byte[ms.Length];
ms.Read(enkNewByte, 0, enkNewByte.Length);
}
}
return enkNeyByte;
}
public byte[] Dekrypt(byte[] enkByte)
{
byte[] dekByte;
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, DekValue, CryptoStreamMode.Write))
{
cs.Write(enkByte, 0, enkByte.Length);
cs.FlushFinalBlock();
ms.Position = 0;
dekByte= new byte[ms.Length];
ms.Read(dekByte, 0, dekByte.Length);
}
}
return dekByte;
}
}
Convert password from text box to byte array...
private byte[] ConvertPasswordToByte(string password)
{
byte[] key = new byte[32];
for (int i = 0; i < passwprd.Length; i++)
{
key[i] = Convert.ToByte(passwprd[i]);
}
return key;
}

here is a neat and clean code to understand AES 256 algorithm implemented in C#
call Encrypt function as encryptedstring = cryptObj.Encrypt(username, "AGARAMUDHALA", "EZHUTHELLAM", "SHA1", 3, "#1B2c3D4e5F6g7H8", 256);
public class Crypt
{
public string Encrypt(string passtext, string passPhrase, string saltV, string hashstring, int Iterations, string initVect, int keysize)
{
string functionReturnValue = null;
// Convert strings into byte arrays.
// Let us assume that strings only contain ASCII codes.
// If strings include Unicode characters, use Unicode, UTF7, or UTF8
// encoding.
byte[] initVectorBytes = null;
initVectorBytes = Encoding.ASCII.GetBytes(initVect);
byte[] saltValueBytes = null;
saltValueBytes = Encoding.ASCII.GetBytes(saltV);
// Convert our plaintext into a byte array.
// Let us assume that plaintext contains UTF8-encoded characters.
byte[] plainTextBytes = null;
plainTextBytes = Encoding.UTF8.GetBytes(passtext);
// First, we must create a password, from which the key will be derived.
// This password will be generated from the specified passphrase and
// salt value. The password will be created using the specified hash
// algorithm. Password creation can be done in several iterations.
PasswordDeriveBytes password = default(PasswordDeriveBytes);
password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashstring, Iterations);
// Use the password to generate pseudo-random bytes for the encryption
// key. Specify the size of the key in bytes (instead of bits).
byte[] keyBytes = null;
keyBytes = password.GetBytes(keysize/8);
// Create uninitialized Rijndael encryption object.
RijndaelManaged symmetricKey = default(RijndaelManaged);
symmetricKey = new RijndaelManaged();
// It is reasonable to set encryption mode to Cipher Block Chaining
// (CBC). Use default options for other symmetric key parameters.
symmetricKey.Mode = CipherMode.CBC;
// Generate encryptor from the existing key bytes and initialization
// vector. Key size will be defined based on the number of the key
// bytes.
ICryptoTransform encryptor = default(ICryptoTransform);
encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
// Define memory stream which will be used to hold encrypted data.
MemoryStream memoryStream = default(MemoryStream);
memoryStream = new MemoryStream();
// Define cryptographic stream (always use Write mode for encryption).
CryptoStream cryptoStream = default(CryptoStream);
cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
// Start encrypting.
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
// Finish encrypting.
cryptoStream.FlushFinalBlock();
// Convert our encrypted data from a memory stream into a byte array.
byte[] cipherTextBytes = null;
cipherTextBytes = memoryStream.ToArray();
// Close both streams.
memoryStream.Close();
cryptoStream.Close();
// Convert encrypted data into a base64-encoded string.
string cipherText = null;
cipherText = Convert.ToBase64String(cipherTextBytes);
functionReturnValue = cipherText;
return functionReturnValue;
}
public string Decrypt(string cipherText, string passPhrase, string saltValue, string hashAlgorithm, int passwordIterations, string initVector, int keySize)
{
string functionReturnValue = null;
// Convert strings defining encryption key characteristics into byte
// arrays. Let us assume that strings only contain ASCII codes.
// If strings include Unicode characters, use Unicode, UTF7, or UTF8
// encoding.
byte[] initVectorBytes = null;
initVectorBytes = Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = null;
saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
// Convert our ciphertext into a byte array.
byte[] cipherTextBytes = null;
cipherTextBytes = Convert.FromBase64String(cipherText);
// First, we must create a password, from which the key will be
// derived. This password will be generated from the specified
// passphrase and salt value. The password will be created using
// the specified hash algorithm. Password creation can be done in
// several iterations.
PasswordDeriveBytes password = default(PasswordDeriveBytes);
password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations);
// Use the password to generate pseudo-random bytes for the encryption
// key. Specify the size of the key in bytes (instead of bits).
byte[] keyBytes = null;
keyBytes = password.GetBytes(keySize / 8);
// Create uninitialized Rijndael encryption object.
RijndaelManaged symmetricKey = default(RijndaelManaged);
symmetricKey = new RijndaelManaged();
// It is reasonable to set encryption mode to Cipher Block Chaining
// (CBC). Use default options for other symmetric key parameters.
symmetricKey.Mode = CipherMode.CBC;
// Generate decryptor from the existing key bytes and initialization
// vector. Key size will be defined based on the number of the key
// bytes.
ICryptoTransform decryptor = default(ICryptoTransform);
decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
// Define memory stream which will be used to hold encrypted data.
MemoryStream memoryStream = default(MemoryStream);
memoryStream = new MemoryStream(cipherTextBytes);
// Define memory stream which will be used to hold encrypted data.
CryptoStream cryptoStream = default(CryptoStream);
cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
// Since at this point we don't know what the size of decrypted data
// will be, allocate the buffer long enough to hold ciphertext;
// plaintext is never longer than ciphertext.
byte[] plainTextBytes = null;
plainTextBytes = new byte[cipherTextBytes.Length + 1];
// Start decrypting.
int decryptedByteCount = 0;
decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
// Close both streams.
memoryStream.Close();
cryptoStream.Close();
// Convert decrypted data into a string.
// Let us assume that the original plaintext string was UTF8-encoded.
string plainText = null;
plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
// Return decrypted string.
functionReturnValue = plainText;
return functionReturnValue;
}
}

Related

I want to decrypt text using the crypto.js library in an Angular application that is encrypted using AES encryption with the .NET System.Security.Cryptography library.
To encrypt using C# I use the following method:
private void FileEncrypt(string inputFile, string password)
{
byte[] salt = GenerateSalt();
byte[] passwords = Encoding.UTF8.GetBytes(password);
RijndaelManaged AES = new RijndaelManaged();
AES.KeySize = 256;//aes 256 bit encryption c#
AES.BlockSize = 128;//aes 128 bit encryption c#
AES.Padding = PaddingMode.PKCS7;
var key = new Rfc2898DeriveBytes(passwords, salt, 50000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CFB;
using (FileStream fsCrypt = new FileStream(inputFile + ".aes", FileMode.Create))
{
fsCrypt.Write(salt, 0, salt.Length);
using (CryptoStream cs = new CryptoStream(fsCrypt, AES.CreateEncryptor(), CryptoStreamMode.Write))
{
using (FileStream fsIn = new FileStream(inputFile, FileMode.Open))
{
byte[] buffer = new byte[1048576];
int read;
while ((read = fsIn.Read(buffer, 0, buffer.Length)) > 0)
{
cs.Write(buffer, 0, read);
}
}
}
}
}
the GenerateSalt() method generates a cryptographically strong sequence of random byte values.
And to decrypt the following:
private void FileDecrypt(string inputFileName, string outputFileName, string password)
{
byte[] passwords = Encoding.UTF8.GetBytes(password);
byte[] salt = new byte[32];
using (FileStream fsCrypt = new FileStream(inputFileName, FileMode.Open))
{
fsCrypt.Read(salt, 0, salt.Length);
RijndaelManaged AES = new RijndaelManaged();
AES.KeySize = 256;//aes 256 bit encryption c#
AES.BlockSize = 128;//aes 128 bit encryption c#
AES.Padding = PaddingMode.PKCS7;
var key = new Rfc2898DeriveBytes(passwords, salt, 50000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CFB;
using (CryptoStream cryptoStream = new CryptoStream(fsCrypt, AES.CreateDecryptor(), CryptoStreamMode.Read))
{
using (FileStream fsOut = new FileStream(outputFileName.Replace(".aes",""), FileMode.Create))
{
int read;
byte[] buffer = new byte[1048576];
while ((read = cryptoStream.Read(buffer, 0, buffer.Length)) > 0)
{
fsOut.Write(buffer, 0, read);
}
}
}
}
}
To do a decryption test in angular using the crypto.js library, I used the following code:
convertText(conversion:string) {
var C = CryptoJS;
if (conversion=="encrypt") {
this.conversionEncryptOutput = CryptoJS.AES.encrypt(this.plainText.trim(), this.encPassword.trim()).toString();
}
else {
var C = CryptoJS;
this.conversionDecryptOutput = CryptoJS.AES.decrypt(
this.encryptText.toString(),
this.decPassword.trim(), {
mode: C.mode.CFB,
padding: C.pad.Pkcs7
}).toString(CryptoJS.enc.Utf8);
}
}
I get the following error when trying to decrypt a pre-encrypted text using the C# method
enter image description here
ERROR Error: Malformed UTF-8 data
at Object.stringify (core.js:523:1)
at WordArray.init.toString (core.js:278:1)
at AppComponent.convertText (app.component.ts:36:14)
at AppComponent_Template_button_click_37_listener (app.component.html:39:74)
at executeListenerWithErrorHandling (core.js:15327:1)
at wrapListenerIn_markDirtyAndPreventDefault (core.js:15365:1)
at HTMLButtonElement.<anonymous> (platform-browser.js:561:1)
at _ZoneDelegate.invokeTask (zone.js:406:1)
at Object.onInvokeTask (core.js:28679:1)
at _ZoneDelegate.invokeTask (zone.js:405:1)

I'm triying to Encrypt string with C# and decrypt it using Angular crypto-js library but it's giving me different output.
I tried different c# aes encryption implementations but crypto-js library can't decrypt the encrypted data in c#. Thank you for any help.
Here is my code
Program.cs
static void Main()
{
var r = EncryptString("exampleString", "examplePassword");
Console.Write(r);
}
public static string EncryptString(string plainText, string passPhrase)
{
if (string.IsNullOrEmpty(plainText))
{
return "";
}
// generate salt
byte[] key, iv;
var salt = new byte[8];
var rng = new RNGCryptoServiceProvider();
rng.GetNonZeroBytes(salt);
DeriveKeyAndIv(passPhrase, salt, out key, out iv);
// encrypt bytes
var encryptedBytes = EncryptStringToBytesAes(plainText, key, iv);
// add salt as first 8 bytes
var encryptedBytesWithSalt = new byte[salt.Length + encryptedBytes.Length + 8];
Buffer.BlockCopy(Encoding.ASCII.GetBytes("Salted__"), 0, encryptedBytesWithSalt, 0, 8);
Buffer.BlockCopy(salt, 0, encryptedBytesWithSalt, 8, salt.Length);
Buffer.BlockCopy(encryptedBytes, 0, encryptedBytesWithSalt, salt.Length + 8, encryptedBytes.Length);
// base64 encode
return Convert.ToBase64String(encryptedBytesWithSalt);
}
private static void DeriveKeyAndIv(string passPhrase, byte[] salt, out byte[] key, out byte[] iv)
{
// generate key and iv
var concatenatedHashes = new List<byte>(48);
var password = Encoding.UTF8.GetBytes(passPhrase);
var currentHash = new byte[0];
var md5 = MD5.Create();
bool enoughBytesForKey = false;
// See http://www.openssl.org/docs/crypto/EVP_BytesToKey.html#KEY_DERIVATION_ALGORITHM
while (!enoughBytesForKey)
{
var preHashLength = currentHash.Length + password.Length + salt.Length;
var preHash = new byte[preHashLength];
Buffer.BlockCopy(currentHash, 0, preHash, 0, currentHash.Length);
Buffer.BlockCopy(password, 0, preHash, currentHash.Length, password.Length);
Buffer.BlockCopy(salt, 0, preHash, currentHash.Length + password.Length, salt.Length);
currentHash = md5.ComputeHash(preHash);
concatenatedHashes.AddRange(currentHash);
if (concatenatedHashes.Count >= 48)
enoughBytesForKey = true;
}
key = new byte[32];
iv = new byte[16];
concatenatedHashes.CopyTo(0, key, 0, 32);
concatenatedHashes.CopyTo(32, iv, 0, 16);
md5.Clear();
}
static byte[] EncryptStringToBytesAes(string plainText, byte[] key, byte[] iv)
{
// Check arguments.
if (plainText == null || plainText.Length <= 0)
throw new ArgumentNullException("plainText");
if (key == null || key.Length <= 0)
throw new ArgumentNullException("key");
if (iv == null || iv.Length <= 0)
throw new ArgumentNullException("iv");
// Declare the stream used to encrypt to an in memory
// array of bytes.
MemoryStream msEncrypt;
// Declare the RijndaelManaged object
// used to encrypt the data.
RijndaelManaged aesAlg = null;
try
{
// Create a RijndaelManaged object
// with the specified key and IV.
aesAlg = new RijndaelManaged { Mode = CipherMode.CBC, KeySize = 256, BlockSize = 128, Key = key, IV = iv };
// Create an encryptor to perform the stream transform.
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for encryption.
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);
swEncrypt.Flush();
swEncrypt.Close();
}
}
}
finally
{
// Clear the RijndaelManaged object.
aesAlg?.Clear();
}
// Return the encrypted bytes from the memory stream.
return msEncrypt.ToArray();
}
Simply decrypting it using crypto-js
let CryptoJS = require('crypto-js');
let r = CryptoJS.AES.decrypt('exampleString', 'examplePassword').toString();

The example code is attempting to decrypt the original unencrypted string, which looks to be a mistake perhaps created when trying to simplify the example code for posting the question? Either way the steps required are not too difficult, but the toString() call needs to be replaced.
var data = "U2FsdGVkX1/Zvh/5BnLfUgfbg5ROSD7Aohumr9asPM8="; // Output from C#
let r2 = CryptoJS.enc.Utf8.stringify(CryptoJS.AES.decrypt(data, 'examplePassword'));
console.log(r2);

I need to take working JavaScript that decrypts a message and convert it into C#. I have the decryption information (the "decrypt" variable below) which looks like: AES-128:<salt>:<iv>:<key>. Here's the JavaScript:
function decodeString(message, decrypt) {
var parts = decrypt.split(':', 4);
var salt = CryptoJS.enc.Hex.parse(parts[1]);
var iv = CryptoJS.enc.Hex.parse(parts[2]);
var key = CryptoJS.PBKDF2(parts[3], salt, { keySize: 128/32, iterations: 100 });
try {
message = message.replace(/\s+/g, '');
var d = CryptoJS.AES.decrypt(message, key, { iv: iv, mode: CryptoJS.mode.CBC, padding: CryptoJS.pad.Pkcs7 });
message = d.toString(CryptoJS.enc.Utf8);
} catch (e) {
console.error("Encountered a problem decrypting and encrypted page!");
console.log(e);
}
return(message);
}
Here's what I have in C#, but I get an exception on the CreateDecryptor call.
using System.Security.Cryptography;
private string DecodeString(string message, string decrypt)
{
string[] parts = decrypt.ToString().Split(':');
byte[] salt = Encoding.UTF8.GetBytes(parts[1]);
byte[] iv = Encoding.UTF8.GetBytes(parts[2]);
var pbkdf2 = new Rfc2898DeriveBytes(parts[3], salt, 100);
int numKeyBytes = 128; // Not sure this is correct
byte[] key = pbkdf2.GetBytes(numKeyBytes);
string plainText = null;
using (AesManaged aes = new AesManaged())
{
aes.KeySize = numKeyBytes; // Not sure if this is correct
aes.BlockSize = 128; // Defaults to 128, but not sure this is correct
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
try
{
// The below line has the following exception:
// The specified key is not a valid size for this algorithm.
// Parameter name: key
using (var decrypter = aes.CreateDecryptor(key, iv))
using (var plainTextStream = new MemoryStream())
{
using (var decrypterStream = new CryptoStream(plainTextStream, decrypter, CryptoStreamMode.Write))
using (var binaryWriter = new BinaryWriter(decrypterStream))
{
string encryptedText = Regex.Replace(message, #"\s+", "");
binaryWriter.Write(encryptedText);
}
byte[] plainTextBytes = plainTextStream.ToArray();
plainText = Encoding.UTF8.GetString(plainTextBytes);
}
}
catch (Exception ex)
{
log.Error("Unable to decrypt message.", ex);
}
return plainText;
}
}
Any suggestions would be appreciated!

In the C# code there are the following issues:
Salt and IV must be hex decoded (and not UTF8 encoded).
numKeyBytes specifies the key size in bytes and is therefore 16 (and not 128) for AES-128.
aes.KeySize specifies the key size in bits and is therefore numKeyBytes * 8 (and not numKeyBytes), but can alternatively be omitted.
For aes.BlockSize, aes.Mode and aes.Padding the default values are used (128, CBC, PKCS7), so they do not need to be specified explicitly.
encryptedText must be Base64 decoded.
A possible implementation is:
private string Decrypt(string message, string decrypt)
{
string[] parts = decrypt.ToString().Split(':');
byte[] salt = StringToByteArray(parts[1]); // Hex decode salt
byte[] iv = StringToByteArray(parts[2]); // Hex dedoce IV
var pbkdf2 = new Rfc2898DeriveBytes(parts[3], salt, 100);
int numKeyBytes = 16; // AES-128 key size in bytes: 16
byte[] key = pbkdf2.GetBytes(numKeyBytes);
string plainText = null;
using (AesManaged aes = new AesManaged())
{
aes.KeySize = 192;
try
{
string encryptedText = Regex.Replace(message, #"\s+", "");
using (var decrypter = aes.CreateDecryptor(key, iv))
using (MemoryStream msDecrypt = new MemoryStream(Convert.FromBase64String(encryptedText))) // Base64 decode ciphertext
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decrypter, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
plainText = srDecrypt.ReadToEnd();
}
}
}
}
catch (Exception ex)
{
Console.WriteLine("Unable to decrypt message.", ex);
}
return plainText;
}
}
where StringToByteArray() is from here.
I changed the Stream part to be analogous to this example, but the original implementation works as well, so this change is optional.
Test: Both codes return for the data
message = "YhyXEjjNAnRUUONwVzlha59tRoWkeEwTkOtSKOicRd/iBKkGgIp+DeWmvEXxAU53";
decrypt = "AES-128:30313233343536373839303132333435:35343332313039383736353433323130:my passphrase";
the plaintext:
The quick brown fox jumps over the lazy dog

I found this code in c#. Its a dummy question but I don't know anything about encryption. This code encrypt and decrypt but there is no password field where should I put. This is the code that I found which is compatible with the java-script code so I really want it to work at last. Thank you :
using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
using System.Security.Cryptography;
using System.Diagnostics;
using System.IO;
namespace Rextester
{
class Program
{
public static void Main(string[] args)
{
string s = "Please enter UserName";
var encry = EncryptStringAES(s);
var dec = DecryptStringAES(encry);
Console.WriteLine(encry);
Console.WriteLine(dec);
Console.Write("Press any key to continue . . . ");
Console.ReadKey(true);
}
public static string DecryptStringAES(string cipherText)
{
var keybytes = Encoding.UTF8.GetBytes("8080808080808080");
var iv = Encoding.UTF8.GetBytes("8080808080808080");
var encrypted = Convert.FromBase64String(cipherText);
var decriptedFromJavascript = DecryptStringFromBytes(encrypted, keybytes, iv);
return string.Format(decriptedFromJavascript);
}
private static string DecryptStringFromBytes(byte[] cipherText, byte[] key, byte[] iv)
{
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
{
throw new ArgumentNullException("cipherText");
}
if (key == null || key.Length <= 0)
{
throw new ArgumentNullException("key");
}
if (iv == null || iv.Length <= 0)
{
throw new ArgumentNullException("key");
}
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
// Create an RijndaelManaged object
// with the specified key and IV.
using (var rijAlg = new RijndaelManaged())
{
//Settings
rijAlg.Mode = CipherMode.CBC;
rijAlg.Padding = PaddingMode.PKCS7;
rijAlg.FeedbackSize = 128;
rijAlg.Key = key;
rijAlg.IV = iv;
// Create a decrytor to perform the stream transform.
var decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
try
{
// 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();
}
}
}
}
catch
{
plaintext = "keyError";
}
}
return plaintext;
}
public static string EncryptStringAES(string plainText)
{
var keybytes = Encoding.UTF8.GetBytes("8080808080808080");
var iv = Encoding.UTF8.GetBytes("8080808080808080");
var encryoFromJavascript = EncryptStringToBytes(plainText, keybytes, iv);
return Convert.ToBase64String(encryoFromJavascript);
}
private static byte[] EncryptStringToBytes(string plainText, byte[] key, byte[] iv)
{
// Check arguments.
if (plainText == null || plainText.Length <= 0)
{
throw new ArgumentNullException("plainText");
}
if (key == null || key.Length <= 0)
{
throw new ArgumentNullException("key");
}
if (iv == null || iv.Length <= 0)
{
throw new ArgumentNullException("key");
}
byte[] encrypted;
// Create a RijndaelManaged object
// with the specified key and IV.
using (var rijAlg = new RijndaelManaged())
{
rijAlg.Mode = CipherMode.CBC;
rijAlg.Padding = PaddingMode.PKCS7;
rijAlg.FeedbackSize = 128;
rijAlg.Key = key;
rijAlg.IV = iv;
// Create a decrytor to perform the stream transform.
var encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.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();
}
}
}
// Return the encrypted bytes from the memory stream.
return encrypted;
}
}
}
The java-script I know where to put the password but in c# I don't know:
<script src="http://crypto-js.googlecode.com/svn/tags/3.1.2/build/rollups/aes.js "></script>
<script type="text/javascript">
function SubmitsEncry() {
debugger;
var txtUserName = "Please enter UserName";
var key = CryptoJS.enc.Utf8.parse('8080808080808080');
var iv = CryptoJS.enc.Utf8.parse('8080808080808080');
var encrypted = CryptoJS.AES.encrypt(CryptoJS.enc.Utf8.parse(txtUserName),'1', key,
{
keySize: 128 / 8,
iv: iv,
mode: CryptoJS.mode.CBC,
padding: CryptoJS.pad.Pkcs7
});
var decrypted = CryptoJS.AES.decrypt(encrypted,'1', key,
{
keySize: 128 / 8,
iv: iv,
mode: CryptoJS.mode.CBC,
padding: CryptoJS.pad.Pkcs7
});
alert(encrypted);
}
SubmitsEncry();
</script>

I'm not sure I fully understand the extent of your question, but if it is as simple as it appears to be, you could always Ctrl-F to find the key in the C# code. It's the line that starts with var keybytes = Encoding.UTF8.GetBytes("80...
However, the code that you have isn't going to do what you want. It is insecure and easily broken (since the key is literally in the code). Your lack of understanding of cryptography in general is also going to limit your ability to create the solution I think you are envisioning.
Some advice:
If you want to use a password, you need to understand that this is fundamentally different from a key. Use a KDF to derive a key from a password. PBKDF2 is good.
Don't use a fixed IV. If the IV remains the same then you compromise the encryption. It should be different every time you encrypt. It doesn't need to be secret at all, just different.
Use an authenticated mode if you can (GCM), otherwise use an HMAC to authenticate your ciphertext. If you don't do this, anyone can change the contents of the file (even if it is encrypted) and you won't know that this has happened.
I recommend you view the examples in this repository. There are examples for both C# and browser JavaScript.

I have the following Javascript code in a web page:
var decrypt = function (text, password){
var decipher = crypto.createDecipher('aes-256-cbc',password);
var dec = decipher.update(text,'hex','utf8');
dec += decipher.final('utf8');
return dec;
}
, and I'm trying to reproduce it using Java, using the following:
static MessageDigest MD5 = null;
static {
try {
MD5 = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}
public static String decrypt(String cipherText, String password)
throws GeneralSecurityException, UnsupportedEncodingException {
byte[] passwordBytes = hexStringToByteArray(password);
byte[] keyBytes = MD5.digest(passwordBytes);
byte[] keyAndPassword = new byte[keyBytes.length + passwordBytes.length];
System.arraycopy(keyBytes, 0, keyAndPassword, 0, keyBytes.length);
System.arraycopy(passwordBytes, 0, keyAndPassword, keyBytes.length, passwordBytes.length);
byte[] ivBytes = MD5.digest(keyAndPassword);
SecretKeySpec key = new SecretKeySpec(keyBytes, "AES");
IvParameterSpec iv = new IvParameterSpec(ivBytes);
byte[] encrypted = hexStringToByteArray(cipherText);
Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");
aesCBC.init(Cipher.DECRYPT_MODE, key, iv);
byte[] decryptedData = aesCBC.doFinal(encrypted);
return new String(decryptedData, StandardCharsets.UTF_8);
}
public static byte[] hexStringToByteArray(String s) {
int len = s.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i + 1), 16));
}
return data;
}
which pieces bits from:
Encrypt with Node.js Crypto module and decrypt with Java (in Android app)
CryptoJS AES encryption and Java AES decryption
, but I get "javax.crypto.BadPaddingException: Given final block not properly padded", on parameters which the JS function decodes correctly.
Note that Given final block not properly padded does not answer this question- as it is obvious that this is a padding problem but the solution is to replicate whatever the JS crypto lib does, which is not well documented.