Here is the C# code I'm trying to port into Node crypto, but since I don't know c# it's proving a little tricky!
public static string EncryptStringToBytes_Aes(string username, string password)
{
string encrypted = string.Empty;
byte[] clearBytes = Encoding.UTF8.GetBytes(password);
Console.WriteLine("1." + clearBytes);
using (Aes aesAlg = Aes.Create())
{
byte[] k; byte[] iv;
byte[] bytes = Encoding.UTF8.GetBytes(username);
k = SHA256.Create().ComputeHash(bytes);
iv = MD5.Create().ComputeHash(bytes);
aesAlg.Key = k;
aesAlg.IV = iv;
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)) {
csEncrypt.Write(clearBytes, 0, clearBytes.Length); }
encrypted = Convert.ToBase64String(msEncrypt.ToArray());
}
}
return encrypted;
}
C# repl:
https://repl.it/#HarryLincoln/NegligiblePoisedHexagon
Node workings:
crypto.createCipheriv() definitely looks like the way to go, but the I don't believe the c# methods (SHA256.Create() & MD5.Create()) care for the length of the key and iv - but crypto.createCipheriv() does.
The c# uses a CryptoStream: So I think some kind of Buffer is in order looking at some similar C# -> Node crypto stuff
Would really appreciate some help!
.Net Framework - AES encryption uses a 256 bit key and CBC mode and PKCS7 padding by default.
The code to port is very simple to read, it just does this:
return
BASE64 (
AES_ENCRYPT (
password,
Key: SHA256(username),
IV: MD5(username)
)
)
The same can easily be achieved on Node.
const crypto = require('crypto');
const key = crypto.createHash('sha256').update('username', 'utf8').digest();
const iv = crypto.createHash('md5').update('username', 'utf8').digest();
const encryptor = crypto.createCipheriv("aes-256-cbc", key, iv);
var crypted = Buffer.concat([encryptor.update('password', 'utf8'), encryptor.final()]);
let base64data = crypted.toString('base64');
console.log(base64data);
Related
I have this code in CryptoJS, inside browser:
var decrypt = function (cipherText) {
var key = "a_long_key_goes_here";
var iv = "initial_vector_goes_here";
key = CryptoJS.enc.Hex.parse(key);
iv = CryptoJS.enc.Hex.parse(iv);
var decrypted = CryptoJS.TripleDES.decrypt({
ciphertext: CryptoJS.enc.Hex.parse(cipherText)
}, key, {
iv: iv,
mode: CryptoJS.mode.CBC
});
var clearText = decrypted.toString(CryptoJS.enc.Utf8);
return clearText;
};
This code is not written by me. Also the cipherText come from another server that I have no access to. However, I have access to key and to iv.
I can decrypt that cipherText inside a browser's console. But I want to use these keys to decrypt that cipherText inside C# code. Here's the code I've written:
public void Desrypt()
{
ICryptoTransform decryptor;
UTF8Encoding encoder;
string key = "a_long_key_goes_here";
string iv = "initial_vector_goes_here";
var cipherText = "cipher_text_goes_here";
string clearText = "";
byte[] cipherBytes = FromHexString(cipherText);
using (Aes aes = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(key, new byte[] { });
aes.Key = pdb.GetBytes(32);
aes.IV = pdb.GetBytes(16);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(cipherBytes, 0, cipherBytes.Length);
cs.Close();
}
clearText = Encoding.Unicode.GetString(ms.ToArray());
}
}
return clearText;
}
public static byte[] FromHexString(string hexString)
{
var bytes = new byte[hexString.Length / 2];
for (var i = 0; i < bytes.Length; i++)
{
bytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
}
return bytes;
}
I have some problems though. I don't understand if I'm correctly decoding the given cipherText from hexadecimal or not. Also I can't instantiate Rfc2898DeriveBytes, because I don't know what the second parameter (salt) should be.
Also I don't know where should I use that iv I've gotten from the CryptoJS code.
Could you please help?
So that both codes are compatible, the following changes of the C# code are necessary:
The return type of the Decrypt method must be changed from void to string.
Key and IV have to be decoded hexadecimal like the ciphertext with FromHexString.
Instead of AES, TripleDES must be used.
Rfc2898DeriveBytes implements PBKDF2 and must not be applied (since the JavaScript code does not use PBKDF2 either).
The decrypted data must not be decoded with Encoding.Unicode (which corresponds to UTF16LE in .NET), but with Encoding.UTF8.
The C# code can handle 24 bytes keys (to support 3TDEA) and 16 bytes keys (to support the less secure 2TDEA). The posted CryptoJS code also handles these key sizes plus additionally 8 bytes keys (to support the least secure, DES compatible variant 1TDEA).
The following C# code decrypts a ciphertext generated with CryptoJS and 3TDEA:
public string Decrypt()
{
byte[] key = FromHexString("000102030405060708090a0b0c0d0e0f1011121314151617"); // 24 bytes (3TDEA)
byte[] iv = FromHexString("0001020304050607"); // 8 bytes
byte[] ciphertext = FromHexString("2116057c372e0e95dbe91fbfd148371b8e9974187b71e7c018de89c757280ad342d4191d29472040ee70d19015b025e1");
string plaintext = "";
using (TripleDES tdes = TripleDES.Create())
{
tdes.Key = key;
tdes.IV = iv;
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, tdes.CreateDecryptor(tdes.Key, tdes.IV), CryptoStreamMode.Write))
{
cs.Write(ciphertext, 0, ciphertext.Length);
}
plaintext = Encoding.UTF8.GetString(ms.ToArray());
}
}
return plaintext;
}
The decryption is also possible with the posted JavaScript code, which shows the functional equivalence of both codes.
Note: Since AES is more performant than TripleDES, AES should be used if possible.
Python Encryption:
salt = 16 * b'\0'
keyIV = PBKDF2(Config.SECRET, salt).read(48)
key = keyIV[:32]
iv = keyIV[-16:]
aes = AES.new(key, AES.MODE_CBC, iv)
# padding
length = 16 - (len(textToEncrypt) % 16)
print(len(textToEncrypt))
textToEncrypt += length * b'\0'
encrypted = aes.encrypt(textToEncrypt)
encoded = base64.b64encode(encrypted)
return encoded
And here is my C# decryption:
textToDecrypt = textToDecrypt.Replace(" ", "+");
byte[] bytesToDecrypt = Convert.FromBase64String(textToDecrypt);
string decryptedText;
using (Aes aes = Aes.Create())
{
byte[] salt = new byte[16];
Rfc2898DeriveBytes crypto = new Rfc2898DeriveBytes(Config.SECRET, salt);
aes.Padding = PaddingMode.PKCS7;
aes.Mode = CipherMode.CBC;
aes.Key = crypto.GetBytes(32);
aes.IV = crypto.GetBytes(16);
using (MemoryStream mStream = new MemoryStream())
{
using (CryptoStream cStream = new CryptoStream(mStream, aes.CreateDecryptor(), CryptoStreamMode.Write))
{
cStream.Write(bytesToDecrypt, 0, bytesToDecrypt.Length);
}
decryptedText = Encoding.Unicode.GetString(mStream.ToArray());
}
}
return decryptedText;
EDIT
Following #kelalaka answer, I'm now able to encrypt from C# and decrypt that string in python successfully, but not vice versa. That is, if I encrypt a string in python, and try to decrypt that encryption in C# I get an exception: "Bad PKCS7 padding. Invalid length 0". My python encryption is much shorter than what I get in C# using the same cipherText, iv, and key.
I am trying to write code to decrypt a string.
I was given an equivalent in python and I am trying to create the same in . NET
Python:
//Initialization vector is just a string of 16 null bytes
iv = '\x00' * 16
//Create new AES object using the key and init vector
aes = AES.new(key, AES.MODE_CBC, iv)
//Decrypt password and remove padding
result = aes.decrypt(myString).rstrip('\x0b\x08\x07')
return result
Here is my attempt:
byte[] iv = new byte[16];
byte[] rawPlaintext = Convert.FromBase64String("MyBase64String");
byte[] key = // Read from common source
using (Aes aes = new AesManaged())
{
aes.Padding = PaddingMode.None;
aes.KeySize = 128; // in bits
aes.Key = new byte[128 / 8]; // 16 bytes for 128 bit encryption
aes.IV = new byte[128 / 8]; // AES needs a 16-byte IV
// Should set Key and IV here. Good approach: derive them from
// a password via Cryptography.Rfc2898DeriveBytes
byte[] cipherText = key;
byte[] plainText = iv;
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, aes.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(rawPlaintext, 0, rawPlaintext.Length);
}
cipherText = ms.ToArray();
}
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(cipherText, 0, cipherText.Length);
}
plainText = ms.ToArray();
}
string s = System.Text.Encoding.Unicode.GetString(plainText);
Console.WriteLine(s);
}
It doesn't appear to be working for the result is a string of symbols.
Possible issues:
- I see a mode of CBC getting set. I'm not sure where that equivalent setting would be. I've tried to play with the PaddingMode.
- Could my iv byte[] be causing the issue? Is the default null or 0?
EDIT:
- From what I am reading AesManaged uses AES in CBC mode so that should be a non-issue.
Try replacing this:
string s = System.Text.Encoding.Unicode.GetString(plainText);
to:
string s = System.Text.Encoding.UTF8.GetString(plainText);
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I have encryption / decryption method in python written as
import base64
from Crypto.Cipher import AES
def get_encrypted_message(message):
"""Return encrypted message."""
length = 16 - (len(message) % 16)
message += chr(length) * length
cipher = AES.new('abcdefghijklmnopqrstuvwxyz123456',
AES.MODE_CBC, 16 * '\x00')
message = cipher.encrypt(message)
return base64.b64encode(message)
def get_decrypted_message(message):
"""Return decrypted message."""
if not message:
return
message = base64.b64decode(message)
cipher = AES.new(
'abcdefghijklmnopqrstuvwxyz123456', AES.MODE_CBC, 16 * '\x00')
msg = cipher.decrypt(message)
return msg.strip()
ENCRYPTED_MSG = get_encrypted_message('123')
print ENCRYPTED_MSG # 5pRIk9MDE3z9caf/ayilIA==
print get_decrypted_message(ENCRYPTED_MSG) # 123
I am now looking for equivalent Windows phone 8.1 C# AES algorithm encryption method. I am new to windows phone development and in my application i have to query data by passing encrypted data.
Please guide or help in writing this simple code. As I am finding it very difficult to get winphone 8.1 c# algo, I dont see any AES algo is available or not as it was available in 8.
Thanks!
WP 8.1 and WinRT
public static string Encrypt2(string password, string plainText)
{
IBuffer passwordBuffer = CryptographicBuffer.ConvertStringToBinary(password, BinaryStringEncoding.Utf8);
IBuffer plainBuffer = CryptographicBuffer.ConvertStringToBinary(plainText, BinaryStringEncoding.Utf8);
IBuffer iv = WindowsRuntimeBuffer.Create(16);
SymmetricKeyAlgorithmProvider symProvider = SymmetricKeyAlgorithmProvider.OpenAlgorithm("AES_CBC_PKCS7");
// create symmetric key from derived password key
CryptographicKey symmKey = symProvider.CreateSymmetricKey(passwordBuffer);
// encrypt data buffer using symmetric key and derived salt material
IBuffer encryptedBuffer = CryptographicEngine.Encrypt(symmKey, plainBuffer, iv);
string encryptedText = CryptographicBuffer.EncodeToBase64String(encryptedBuffer);
return encryptedText;
}
public static string Decrypt2(string password, string encryptedText)
{
IBuffer passwordBuffer = CryptographicBuffer.ConvertStringToBinary(password, BinaryStringEncoding.Utf8);
IBuffer encryptedBuffer = CryptographicBuffer.DecodeFromBase64String(encryptedText);
IBuffer iv = WindowsRuntimeBuffer.Create(16);
SymmetricKeyAlgorithmProvider symProvider = SymmetricKeyAlgorithmProvider.OpenAlgorithm("AES_CBC_PKCS7");
// create symmetric key from derived password material
CryptographicKey symmKey = symProvider.CreateSymmetricKey(passwordBuffer);
// encrypt data buffer using symmetric key and derived salt material
IBuffer plainBuffer = CryptographicEngine.Decrypt(symmKey, encryptedBuffer, iv);
string plainText = CryptographicBuffer.ConvertBinaryToString(BinaryStringEncoding.Utf8, plainBuffer);
return plainText;
}
EVERYTHING ELSE
public static string Encrypt(string password, string plainText)
{
using (var aes = new AesManaged())
{
aes.Key = Encoding.UTF8.GetBytes(password);
aes.IV = new byte[16];
aes.Padding = PaddingMode.PKCS7;
aes.Mode = CipherMode.CBC;
byte[] plainBuffer = Encoding.UTF8.GetBytes(plainText);
using (MemoryStream input = new MemoryStream(plainBuffer))
using (MemoryStream output = new MemoryStream())
using (ICryptoTransform encryptor = aes.CreateEncryptor())
using (CryptoStream cs = new CryptoStream(output, encryptor, CryptoStreamMode.Write))
{
input.CopyTo(cs);
cs.FlushFinalBlock();
string encryptedText = Convert.ToBase64String(output.GetBuffer(), 0, (int)output.Length);
return encryptedText;
}
}
}
public static string Decrypt(string password, string encryptedText)
{
using (var aes = new AesManaged())
{
aes.Key = Encoding.UTF8.GetBytes(password);
aes.IV = new byte[16];
aes.Padding = PaddingMode.PKCS7;
aes.Mode = CipherMode.CBC;
byte[] encryptedBuffer = Convert.FromBase64String(encryptedText);
using (MemoryStream input = new MemoryStream(encryptedBuffer))
using (MemoryStream output = new MemoryStream())
using (ICryptoTransform decryptor = aes.CreateDecryptor())
using (CryptoStream cs = new CryptoStream(input, decryptor, CryptoStreamMode.Read))
{
cs.CopyTo(output);
string plainText = Encoding.UTF8.GetString(output.GetBuffer(), 0, (int)output.Length);
return plainText;
}
}
}
Note that there is a small problem here: I'm using UTF8 for the encoding of both the password and the strPlainText, but python uses bytestring for everything, and bytestring is encoding agnostic (see What is a Python bytestring?).
Example of use:
string result = Encrypt("abcdefghijklmnopqrstuvwxyz123456", "123"); // 5pRIk9MDE3z9caf/ayilIA==
string decrypted = Decrypt("abcdefghijklmnopqrstuvwxyz123456", result); // 123
The method returns the same encrypted result as your example.
A small problem of this piece of code is that the IV (the initialization vector) is initialized with an empty biffer (new byte[16] and 16 * '\x00' in Python). This is a "bad habit". Even using the CBC cyphermode is considered to be "bad".
I'm writing a program at the moment that works under the following scenario:
I've got some confidential log files that I need to backup to a server.
I have a program that generates these log files every day.
These log files would rarely if ever need to be opened.
I have only one RSA public/private key pair.
The program has only the RSA public key.
I generate a random AES key each time the program makes one of these confidential files.
The program uses this AES key to encrypt the log file.
I then use the RSA public key to encrypt the AES Key
I then backup both the AES encrypted file and RSA encrypted AES key to the server.
As far as I understand, that protocol is fitting for my use case.
The issue I'm having is coding it up in C#. I ran into needing an Initialization Vector(IV) for my AES encryption, I tried to encrypt this along with the AES key by using the public RSA key on both. But the 512(2 * 256) size is larger than RSA is happy to encrypt. So I figured out since I created the Initialization Vector randomly each time just like the AES Key, I can add the IV to the front of the AES ciphertext. However, I'm not sure where the code to do this would be inserted in my functions
Any help in the right direction to the "protocol" or other ways to write the IV to the ciphertext would be great. Thank you in advance.
static public Tuple<byte[], byte[]> EncryptAES(byte[] toEncryptAES, RSAParameters RSAPublicKey)
{
byte[] encryptedAES = null;
byte[] encryptedRSA = null;
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
AES.Mode = CipherMode.CBC;
AES.GenerateIV();
AES.GenerateKey();
encryptedRSA = RSAEncrypt(AES.Key, RSAPublicKey);
using (var cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write))
{
ms.Write(AES.IV, 0, AES.KeySize); //DOESNT WORK HERE
//Can't use CS to write it to the stream else it will encrypt along with file
cs.Write(toEncryptAES, 0, toEncryptAES.Length);
cs.Close();
}
encryptedAES = ms.ToArray();
}
}
return new Tuple<byte[], byte[]>(encryptedAES, encryptedRSA);
}
static public byte[] DecryptAES(byte[] toDecryptAES, byte[] AESKeyAndIV, RSAParameters RSAPrivateKey)
{
byte[] AESKey = RSADecrypt(AESKeyAndIV, RSAPrivateKey);
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
AES.Key = AESKey;
ms.Read(AES.IV, 0, AES.KeySize); //Not sure if can read MS here
AES.Mode = CipherMode.CBC;
using (var cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write))
{
//Would I need to move 0 to 256?
cs.Write(toDecryptAES, 0, toDecryptAES.Length);
cs.Close();
}
return ms.ToArray();
}
}
}
You where quite close, write out the IV before you create the CryptoStream
static public Tuple<byte[], byte[]> EncryptAES(byte[] toEncryptAES, RSAParameters RSAPublicKey)
{
byte[] encryptedAES = null;
byte[] encryptedRSA = null;
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
AES.Mode = CipherMode.CBC;
AES.GenerateIV();
AES.GenerateKey();
encryptedRSA = RSAEncrypt(AES.Key, RSAPublicKey);
ms.Write(AES.IV, 0, AES.KeySize); //Move the write here.
using (var cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(toEncryptAES, 0, toEncryptAES.Length);
cs.Close();
}
encryptedAES = ms.ToArray();
}
}
return new Tuple<byte[], byte[]>(encryptedAES, encryptedRSA);
}
For the decrypt, make sure you loop over the read till you have fully read the byte[] for the IV, Stream.Read is not guaranteed to read all the bytes you asked it to read. I usually make a static method ReadFully to ensure all bytes are read.
private static byte[] ReadFully(Stream stream, int length)
{
int offset = 0;
byte[] buffer = new byte[length];
while(offset < length)
{
offset += stream.Read(buffer, offset, length - offset);
}
return buffer;
}
Then just use that method to read in the IV. You also want to use cs.Read not cs.Write to read out the encrypted data and put the stream in to read mode, however it is easier to just use .CopyTo and copy the data to a new MemoryStream.
static public byte[] DecryptAES(byte[] toDecryptAES, byte[] AESKeyAndIV, RSAParameters RSAPrivateKey)
{
byte[] AESKey = RSADecrypt(AESKeyAndIV, RSAPrivateKey);
using (MemoryStream source = new MemoryStream(toDecryptAES))
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
AES.Key = AESKey;
var iv = ReadFully(source, AES.KeySize);
AES.IV = iv;
AES.Mode = CipherMode.CBC;
using (var cs = new CryptoStream(source, AES.CreateDecryptor(), CryptoStreamMode.Read))
{
using(var dest = new MemoryStream())
{
cs.CopyTo(dest);
return dest.ToArray();
}
}
}
}
}
For other readers, note that RSAEncrypt and RSADecrypt are wrappers for calls to the RSACryptoServiceProvider.