I have been requested to encrypt some data while talking to my partner's JAVA API, and he sent me the following details about encryption algorithm:
Algorithm : AES256
Key Size : 256 bits
Encryption Mode: CBC (16 bits blocks, PKCS5Padding with 0)
Output Type : Base-64
Password: 0xA8703827AE586460105696504327B7BB0806FEAE96BD664F89E36868FBB48E3D
IV: is a byte[16] with 0 values
I used the below code, but I didn't get a matched result with him:
public byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
{
byte[] encryptedBytes = null;
byte[] saltBytes = new byte[16] { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
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.Padding = PaddingMode.PKCS7;
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 string EncryptText(string input, string password)
{
byte[] bytesToBeEncrypted = Encoding.UTF8.GetBytes(input);
byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
passwordBytes = SHA256.Create().ComputeHash(passwordBytes);
byte[] bytesEncrypted = AES_Encrypt(bytesToBeEncrypted, passwordBytes);
string result = Convert.ToBase64String(bytesEncrypted);
return result;
}
So, when we tried to encrypt Hello, How are you?, I got a different result and I should get the same result he had as he will decrypt my sent data on his side and will process it. The given example should have this result: TJTojNoVgoqnhCj4uTv1jLBiZU7r+s/0Bm234bHU+S0=
I did some testing and now able to match your expected result.
2 changes to be done.
IV
IV is the easiest, as you said IV = 0, so set IV as follows:
aes.IV = new byte[16];
In AES, IV is 16 bytes. The above would create a byte array of 16 bytes with each value initialized to zero.
Key
The password you have given starts with "0x" - this essentially means that this is hexadecimal representation of the password string. I converted this password to byte array using this
string password = "A8703827AE586460105696504327B7BB0806FEAE96BD664F89E36868FBB48E3D";
Please note I removed the starting "0x" from the above
byte[] passwordBytes = StringToByteArray(password);
The above converts the hexadecimal password representation to a byte array.
In your AES_Encrypt method, directly assign this byte[] as the Key
aes.Key = passwordBytes;
Now, my result is TJTojNoVgoqnhCj4uTv1jLBiZU7r+s/0Bm234bHU+S0= which exactly matches with your expected output.
Related
as in the title, I need to implement in my C# code the equivalent of php's openssl_encrypt method, because I need to call a service on a php page, but we work with c#.
The php code is this:
$textToEncrypt = "test";
$algo = "AES256";
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($algo));
$key = "1234567890987654"; //Not this key, but just same length
$parametri_enc = openssl_encrypt($textToEncrypt , $algo, $key, 0, $iv);
$iv = bin2hex($iv);
I tried many thing, actually my code is:
string textToEncrypt = "test";
string secretCode = "1234567890987654"
// Create sha256 hash
SHA256 mySHA256 = SHA256Managed.Create();
byte[] key = mySHA256.ComputeHash(Encoding.ASCII.GetBytes(secretCode));
// Create secret IV
byte[] iv = new byte[16];
RandomNumberGenerator generator = RandomNumberGenerator.Create();
generator.GetBytes(iv);
string encryptedText = EncryptString(textToEncrypt, key, iv);
// And I try to port also the bin2hex method
var sb = new StringBuilder();
foreach (byte b in iv)
{
sb.AppendFormat("{0:x2}", b);
}
var tokenBytesHex = sb.ToString();
And the method EncryptString is
public static string EncryptString(string plainText, byte[] key, byte[] iv)
{
//Instantiate a new Aes object to perform string symmetric encryption
Aes encryptor = Aes.Create();
encryptor.Mode = CipherMode.CBC;
// Set key and IV
byte[] aesKey = new byte[32];
Array.Copy(key, 0, aesKey, 0, 32);
encryptor.Key = aesKey;
encryptor.IV = iv;
// Instantiate a new MemoryStream object to contain the encrypted bytes
MemoryStream memoryStream = new MemoryStream();
// Instantiate a new encryptor from our Aes object
ICryptoTransform aesEncryptor = encryptor.CreateEncryptor();
// Instantiate a new CryptoStream object to process the data and write it to the
// memory stream
CryptoStream cryptoStream = new CryptoStream(memoryStream, aesEncryptor, CryptoStreamMode.Write);
// Convert the plainText string into a byte array
byte[] plainBytes = Encoding.ASCII.GetBytes(plainText);
// Encrypt the input plaintext string
cryptoStream.Write(plainBytes, 0, plainBytes.Length);
// Complete the encryption process
cryptoStream.FlushFinalBlock();
// Convert the encrypted data from a MemoryStream to a byte array
byte[] cipherBytes = memoryStream.ToArray();
// Close both the MemoryStream and the CryptoStream
memoryStream.Close();
cryptoStream.Close();
// Convert the encrypted byte array to a base64 encoded string
string cipherText = Convert.ToBase64String(cipherBytes, 0, cipherBytes.Length);
// Return the encrypted data as a string
return cipherText;
}
I tried many variation about this porting (that I've found on internet), but without result. If I use a correct encrypted string from my code, I can call the service, so it is working. I need only to encrypt correctly that string, but until now, I've failed
Ok i solved my own problem. I'll share it so if anyone has the same problem, this could work. Basically I saw a decryption c# code here so I update my code in this way
First, I pass my secretCode in string format instead of byte[]
So i changed my method signature in this way:
public static string EncryptString(string plainText, string secretcode, byte[] iv)
and inside I changed the way I manipulate the secretCode (passphrase in php equivalent method)
// Set key and IV
var aesKey = Encoding.ASCII.GetBytes(secretcode);
//pad key out to 32 bytes (256bits) if its too short
if (aesKey.Length < 32)
{
var paddedkey = new byte[32];
Buffer.BlockCopy(aesKey, 0, paddedkey, 0, aesKey.Length);
aesKey = paddedkey;
}
So it worked! No other change, just this two small change from my previous post
Updated method
public static string EncryptString(string plainText, string secretcode, byte[] iv)
{
// Instantiate a new Aes object to perform string symmetric encryption
Aes encryptor = Aes.Create();
encryptor.Mode = CipherMode.CBC;
// Set key and IV
var aesKey = Encoding.ASCII.GetBytes(secretcode);
//pad key out to 32 bytes (256bits) if its too short
if (aesKey.Length < 32)
{
var paddedkey = new byte[32];
Buffer.BlockCopy(aesKey, 0, paddedkey, 0, aesKey.Length);
aesKey = paddedkey;
}
encryptor.Key = aesKey;
encryptor.IV = iv;
// Instantiate a new MemoryStream object to contain the encrypted bytes
MemoryStream memoryStream = new MemoryStream();
// Instantiate a new encryptor from our Aes object
ICryptoTransform aesEncryptor = encryptor.CreateEncryptor();
// Instantiate a new CryptoStream object to process the data and write it to the
// memory stream
CryptoStream cryptoStream = new CryptoStream(memoryStream, aesEncryptor, CryptoStreamMode.Write);
// Convert the plainText string into a byte array
byte[] plainBytes = Encoding.ASCII.GetBytes(plainText);
// Encrypt the input plaintext string
cryptoStream.Write(plainBytes, 0, plainBytes.Length);
// Complete the encryption process
cryptoStream.FlushFinalBlock();
// Convert the encrypted data from a MemoryStream to a byte array
byte[] cipherBytes = memoryStream.ToArray();
// Close both the MemoryStream and the CryptoStream
memoryStream.Close();
cryptoStream.Close();
// Convert the encrypted byte array to a base64 encoded string
string cipherText = Convert.ToBase64String(cipherBytes, 0, cipherBytes.Length);
// Return the encrypted data as a string
return cipherText;
}
I wrote code that decrypts the input string completely. But since this is an ECB mode, I wanted to somehow decrypt not the entire input text, but only a separate block of it.
As far as I understand, ECB AES encrypts in blocks of 8 bytes. How can I add the AES_Decrypt function to it so that it decrypts only the last 8 bytes of the input string, for example.
byte[] bytesToBeDecrypted = new byte[32];
byte[] 8_bytesToBeDecrypted = new byte[8]; // Only 8 bytes of bytesToBeDecrypted
public static byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
{
byte[] decryptedBytes = null;
string salt = "12345678";
Encoding unicode = Encoding.Unicode;
byte[] saltBytes = unicode.GetBytes(salt);
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
AES.Padding = PaddingMode.Zeros;
var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 65535);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.ECB;
using (var cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
cs.Close();
}
decryptedBytes = ms.ToArray();
}
}
return decryptedBytes;
}
You can likely just Seek the MemoryStream with a multiple of 16 bytes from the beginning (or apparently even 16 bytes from the last part of the stream) and then connect the CryptoStream to decrypt whatever is left. With CBC that would be a bit more tricky as you would have to set the IV to the previous ciphertext block, but with ECB this should be a breeze.
Notes:
Of course, you don't need to set the IV for the ECB mode, that should not be required.
Rijndael with a block size of 128 is actually AES. C#/.NET only supports a subset of Rijndael by the way: only 64 increments of the block size and key size are supported, if I remember correctly.
I'd still use aes = Aes.Create() rather than aes = new RijndaelManaged() as that leaves the choice of the AES implementation to the system, and it will probably choose the hardware accelerated one over the managed one.
I am trying to decrypt Aes that was created from the JavaScript AES Encryptor from the CryptoJS library. I am trying to read a string that was encrypted by that library and decrypt it within my C# project using the following:
public static string Decrypt(string message, string secret, string salt = "zAvR2NI87bBx746n") {
return Encoding.UTF8.GetString(AESDecryptBytes(
Encoding.UTF8.GetBytes(message),
Encoding.UTF8.GetBytes(secret),
Encoding.UTF8.GetBytes(salt)
));
}
private static byte[] AESDecryptBytes(byte[] cryptBytes, byte[] passBytes, byte[] saltBytes) {
byte[] clearBytes = null;
// create a key from the password and salt, use 32K iterations
// var key = new Rfc2898DeriveBytes(passBytes, saltBytes, 32768);
var key = new Rfc2898DeriveBytes(passBytes, saltBytes, 1000);
using (Aes aes = new AesManaged()) {
// set the key size to 256
aes.KeySize = 256;
aes.Padding = PaddingMode.PKCS7;
aes.Mode = CipherMode.CBC;
aes.Key = key.GetBytes(aes.KeySize / 8);
aes.IV = key.GetBytes(aes.BlockSize / 8);
using (MemoryStream ms = new MemoryStream()) {
using (CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Write)) {
cs.Write(cryptBytes, 0, cryptBytes.Length);
cs.Close();
}
clearBytes = ms.ToArray();
}
}
return clearBytes;
}
The data was encrypted in JavaScript as follows:
// data is a JSON string
// gs.cryptoSecret is a string of random characters
let saveData = CryptoJS.AES.encrypt(data || '', gs.cryptoSecret).toString()
When I attempt to use my method to decrypt the data I get the following error message:
CryptographicException: Invalid input block size.
Which is triggered by cs.Close();. It could be that secret hasn't been implemented, which I am not exactly sure where that would go in this...
How can I implement this decryptor to work alongside the JavaScript Library?
I have been trying to implement proper IV practice in methods to encrypt and decrypt a UTF-8 string with AES which is then returned as a Base64 string. Using this question as a reference, I have prepended the generated IV to the byte array before the Base64 conversion. I'm having an issue where the decrypt method returns the UTF-8 string with exactly fifty characters of random junk (encryption artifacts?). I don't believe the issue is with the encryption because the decrypt method does consistently return the encrypted string. I think the problem is with one of the other conversion steps but I'm having trouble seeing where this might be coming from. Any help would be wildly appreciated.
Encrypt method
public static string EncryptString(string input, string key)
{
using (var aes = new AesCryptoServiceProvider())
{
aes.Key = System.Convert.FromBase64String(key);
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
byte[] rawData = Encoding.UTF8.GetBytes(input);
// IV is the 16 byte AES Initialization Vector
aes.GenerateIV();
using (var encryptor = aes.CreateEncryptor(aes.Key, aes.IV))
{
using (var ms = new MemoryStream())
{
ms.Write(aes.IV, 0, aes.IV.Length); // aes.IV.Length should be 16
using (var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
cs.Write(rawData, 0, rawData.Length);
cs.FlushFinalBlock();
}
byte[] encryptedData = ms.ToArray();
// this will hold the IV prepended to the encrypted data
byte[] output = new byte[aes.IV.Length + encryptedData.Length];
Array.Copy(aes.IV, output, aes.IV.Length); // save the iv
Array.Copy(encryptedData, 0, output, aes.IV.Length, encryptedData.Length); // save the data
// now encode the whole thing as base 64
return System.Convert.ToBase64String(output);
}
}
}
}
Decrypt method
public static string DecryptString(string input, string key)
{
using (var aes = new AesCryptoServiceProvider())
{
aes.Key = Convert.FromBase64String(key);
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
byte[] rawData = Convert.FromBase64String(input);
byte[] IV = new byte[16]; // aes.IV.Length should be 16
Array.Copy(rawData, IV, IV.Length);
using (var ms = new MemoryStream())
{
using (var cs = new CryptoStream(ms, aes.CreateDecryptor(aes.Key, IV), CryptoStreamMode.Write))
{
using (var binaryWriter = new BinaryWriter(cs))
{
binaryWriter.Write(rawData,IV.Length ,rawData.Length - IV.Length);
}
}
return Encoding.UTF8.GetString(ms.ToArray());
}
}
}
My test
static void Main(string[] args)
{
string payload = "My super secret string";
string key = "tR4mPn7mBQ8G6HWusyFnGk/gqdd/enWiUTr7YbhNrJg=";
Console.WriteLine(payload);
Console.WriteLine(key);
Console.WriteLine("");
string encrypted = EncryptString(payload, key);
Console.WriteLine(encrypted);
Console.WriteLine("");
string decrypted = DecryptString(encrypted, key);
Console.WriteLine(decrypted);
Console.WriteLine(decrypted.Length.ToString() + " " + encrypted.Length.ToString());
Console.ReadKey();
}
Edit to add - this is an example of the output:
�XQ��=F�]�D�?�My super secret string
You are writing the IV to the output twice in EncryptString. First you have:
ms.Write(aes.IV, 0, aes.IV.Length); // aes.IV.Length should be 16
which is the start of encryptedData. You then copy the IV and encryptedData (which already includes the IV) into a new byte array:
// this will hold the IV prepended to the encrypted data
byte[] output = new byte[aes.IV.Length + encryptedData.Length];
Array.Copy(aes.IV, output, aes.IV.Length); // save the iv
Array.Copy(encryptedData, 0, output, aes.IV.Length, encryptedData.Length); // save the data
This doubling of the IV is what is causing the extra bytes.
You don’t need to do the second copying. Just convert encryptedData to base 64 directly and return that:
return System.Convert.ToBase64String(encryptedData);
I've been trying to encrypt and decrypt on both iOS and .NET but I haven't been very successful. I've used this question but I get the error:
Specified initialisation vector (IV) does not match the block size for this algorithm.
Here's my encryption code for Swift using CryptoSwift:
let encrypt = try! "oauth_token".AES_encrypt("my key here (is 32 characters long)", iv: "1234567890123456")
func AES_encrypt(key: String, iv: String) throws -> String {
let data = self.dataUsingEncoding(NSUTF8StringEncoding)
let enc = try AES(key: key, iv: iv, blockMode:.CBC).encrypt(data!.arrayOfBytes(), padding: PKCS7())
let encData = NSData(bytes: enc, length: Int(enc.count))
let base64String: String = encData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0));
let result = String(base64String)
return result
}
And my decryption code for .NET:
public static byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] key, byte[] iv)
{
byte[] decryptedBytes = null;
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
AES.Key = key;
AES.IV = iv;
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;
}
byte[] encrypted_text = Convert.FromBase64String("secret token");
byte[] key = Convert.FromBase64String("32 character key");
byte[] iv = Convert.FromBase64String("0123456789012345");
string plaintext = Convert.ToBase64String(AES_Decrypt(encrypted_text, key, iv));
The block size is 16 bytes (AES.blockSize). Either you're using old version or your AES_encrypt() have some problem (AES_encrypt is not part of CryptoSwift).
Simple example from README:
let input: NSData // data to encrypt
let encrypted = try? input.encrypt(AES(key: "secret0key000000", iv:"0123456789012345"))
or this
// Encrypt string and get Base64 representation of result
let base64: String = try? "my secret string".encrypt(AES(key: "secret0key000000", iv: "0123456789012345"))