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How to decrypt password

This is my .NET core API controller.
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using System.Linq;
using Vantage.Core.Direct.BL;
using Vantage.Core.Direct.DAL.Models;
using VANTAGE_Dashboard.API.Helper;
namespace Vantage.Core.Direct.API.Controllers
{
[Route("[controller]")]
[ApiController]
public class LoginController : ControllerBase
{
private readonly VantageContext _context;
public LoginController(VantageContext context)
{
_context = context;
}
[HttpPost("login")]
public IActionResult Login([FromBody] AvLogin avLogin)
{
if (avLogin == null)
{
return BadRequest();
}
else {
// var user = _context.AvLogins.Where(a => a.Id == avLogin.Id).FirstOrDefault();
var user = _context.AvLogins.Where(a =>
a.Id == avLogin.Id && a.PasswordHash == avLogin.PasswordHash).FirstOrDefault();
if (user != null)
{
return Ok(new
{
StatusCode = 200,
Message = "Logged in Successfully"
});
}
else
{
return NotFound(new
{
StatusCode = 404,
Message= "User Not Found"
}) ;
}
}
}
}
}
This is my decryption class
using System.Security.Cryptography;
using System.Text;
using System;
using System.Configuration;
namespace Vantage.DataAccessLayer
{
public class MD5Encryption
{
private static readonly string SecurityKey = "http://www.2am5ana.c0m";
// Hash an input string and return the hash as
// a 32 character hexadecimal string.
public static string GetMd5Hash(string input)
{
// Create a new instance of the MD5CryptoServiceProvider object.
MD5 md5Hasher = MD5.Create();
// Convert the input string to a byte array and compute the hash.
byte[] data = md5Hasher.ComputeHash(Encoding.Default.GetBytes(input));
// Create a new Stringbuilder to collect the bytes
// and create a string.
StringBuilder sBuilder = new StringBuilder();
// Loop through each byte of the hashed data
// and format each one as a hexadecimal string.
for (int i = 0; i < data.Length; i++)
{
sBuilder.Append(data[i].ToString("x2"));
}
// Return the hexadecimal string.
return sBuilder.ToString();
}
public static string Encrypt(string toEncrypt, bool useHashing)
{
byte[] keyArray;
byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);
//System.Windows.Forms.MessageBox.Show(key);
//If hashing use get hashcode regards to your key
if (useHashing)
{
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(SecurityKey));
//Always release the resources and flush data
// of the Cryptographic service provide. Best Practice
hashmd5.Clear();
}
else
keyArray = UTF8Encoding.UTF8.GetBytes(SecurityKey);
TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
//set the secret key for the tripleDES algorithm
tdes.Key = keyArray;
//mode of operation. there are other 4 modes.
//We choose ECB(Electronic code Book)
tdes.Mode = CipherMode.ECB;
//padding mode(if any extra byte added)
tdes.Padding = PaddingMode.PKCS7;
ICryptoTransform cTransform = tdes.CreateEncryptor();
//transform the specified region of bytes array to resultArray
byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0,
toEncryptArray.Length);
//Release resources held by TripleDes Encryptor
tdes.Clear();
//Return the encrypted data into unreadable string format
return Convert.ToBase64String(resultArray, 0, resultArray.Length);
}
public static string Decrypt(string cipherString, bool useHashing)
{
byte[] keyArray;
//get the byte code of the string
byte[] toEncryptArray = Convert.FromBase64String(cipherString);
if (useHashing)
{
//if hashing was used get the hash code with regards to your key
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(SecurityKey));
//release any resource held by the MD5CryptoServiceProvider
hashmd5.Clear();
}
else
{
//if hashing was not implemented get the byte code of the key
keyArray = UTF8Encoding.UTF8.GetBytes(SecurityKey);
}
TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
//set the secret key for the tripleDES algorithm
tdes.Key = keyArray;
//mode of operation. there are other 4 modes.
//We choose ECB(Electronic code Book)
tdes.Mode = CipherMode.ECB;
//padding mode(if any extra byte added)
tdes.Padding = PaddingMode.PKCS7;
ICryptoTransform cTransform = tdes.CreateDecryptor();
byte[] resultArray = cTransform.TransformFinalBlock(
toEncryptArray, 0, toEncryptArray.Length);
//Release resources held by TripleDes Encryptor
tdes.Clear();
//return the Clear decrypted TEXT
return UTF8Encoding.UTF8.GetString(resultArray);
}
public static string DecryptEntityCon()
{
string connectionString = new System.Data.EntityClient.EntityConnectionStringBuilder
{
Metadata = "res://*/VantageModel.csdl|res://*/VantageModel.ssdl|res://*/VantageModel.msl",
Provider = "System.Data.SqlClient",
ProviderConnectionString = MD5Encryption.Decrypt(ConfigurationManager.ConnectionStrings["VantageConnectionString"].ConnectionString, true) + ";MultipleActiveResultSets=true"
}.ConnectionString;
return connectionString;
}
}
}
now can login using userName-: admin , Password-: 2fe3cb9e21922819e79a2781af74e36d but not decrypt value. how to connect both files decypt password ?

Encrypt a file in c# and decrypt in flutter

I have encrypted a file in c# code using RijndaelManaged which is available in System.Security.Cryptography. This file needs to be transferred to a mobile app developed using dart/flutter and I need it to be decrypted using dart code and present it to the user. How can this be done?
Below shown is the code to do the encryption in c#:
string password = keyPhrase; // Your Key Here
UnicodeEncoding UE = new UnicodeEncoding();
byte[] key = UE.GetBytes(password);
string cryptFile = outputFile;
FileStream fsCrypt = new FileStream(cryptFile, FileMode.Create);
RijndaelManaged RMCrypto = new RijndaelManaged();
CryptoStream cs = new CryptoStream(fsCrypt,
RMCrypto.CreateEncryptor(key, key),
CryptoStreamMode.Write);
FileStream fsIn = new FileStream(inputFile, FileMode.Open);
int data;
while ((data = fsIn.ReadByte()) != -1)
cs.WriteByte((byte)data);
fsIn.Close();
cs.Close();
fsCrypt.Close();
Thank you

I ran into the same problem. After many hours, a solution was found. My code is based on this question1 and question2 Code on C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
var m_strPassPhrase = "YYYYYYYYYYYYYYYYYYY";
var p_strSaltValue = "XXXXXXXXXXXXXXXXX";
var m_strPasswordIterations = 2;
var m_strInitVector = "ZZZZZZZZZZZZZZZZ";
var plainText = "myPassword";
var blockSize = 32;
var saltValueBytes = Encoding.ASCII.GetBytes(p_strSaltValue);
var password = new Rfc2898DeriveBytes(m_strPassPhrase, saltValueBytes, m_strPasswordIterations);
var keyBytes = password.GetBytes(blockSize);
var symmetricKey = new RijndaelManaged();
var initVectorBytes = Encoding.ASCII.GetBytes(m_strInitVector);
var encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
var memoryStream = new System.IO.MemoryStream();
var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
var cipherTextBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
var cipherText = Convert.ToBase64String(cipherTextBytes);
Console.WriteLine(cipherText);
Console.WriteLine("\n end");
}
}
}
For flutter you can use pointycastle
Code on Dart(use decryptString and cryptString methods):
import 'dart:convert';
import 'package:pointycastle/block/aes_fast.dart';
import 'dart:typed_data';
import 'package:pointycastle/export.dart';
import 'package:pointycastle/key_derivators/pbkdf2.dart';
import 'package:pointycastle/paddings/pkcs7.dart';
import 'package:pointycastle/pointycastle.dart';
const KEY_SIZE = 32; // 32 byte key for AES-256
const ITERATION_COUNT = 2;
const SALT = "XXXXXXXXXXXXXXXXX";
const INITIAL_VECTOR = "ZZZZZZZZZZZZZZZZ";
const PASS_PHRASE = "YYYYYYYYYYYYYYYYYYY";
Future<String> cryptString(String text) async {
String encryptedString = "";
final mStrPassPhrase = toUtf8(PASS_PHRASE);
encryptedString =
AesHelper.encrypt(mStrPassPhrase, toUtf8(text), mode: AesHelper.CBC_MODE);
return encryptedString;
}
Future<String> decryptString(String text) async {
String decryptedString = "";
final mStrPassPhrase = toUtf8(PASS_PHRASE);
decryptedString =
AesHelper.decrypt(mStrPassPhrase, toUtf8(text), mode: AesHelper.CBC_MODE);
return decryptedString;
}
///MARK: AesHelper class
class AesHelper {
static const CBC_MODE = 'CBC';
static const CFB_MODE = 'CFB';
static Uint8List deriveKey(dynamic password,
{String salt = '',
int iterationCount = ITERATION_COUNT,
int derivedKeyLength = KEY_SIZE}) {
if (password == null || password.isEmpty) {
throw new ArgumentError('password must not be empty');
}
if (password is String) {
password = createUint8ListFromString(password);
}
Uint8List saltBytes = createUint8ListFromString(salt);
Pbkdf2Parameters params =
new Pbkdf2Parameters(saltBytes, iterationCount, derivedKeyLength);
KeyDerivator keyDerivator =
new PBKDF2KeyDerivator(new HMac(new SHA1Digest(), 64));
keyDerivator.init(params);
return keyDerivator.process(password);
}
static Uint8List pad(Uint8List src, int blockSize) {
var pad = new PKCS7Padding();
pad.init(null);
int padLength = blockSize - (src.length % blockSize);
var out = new Uint8List(src.length + padLength)..setAll(0, src);
pad.addPadding(out, src.length);
return out;
}
static Uint8List unpad(Uint8List src) {
var pad = new PKCS7Padding();
pad.init(null);
int padLength = pad.padCount(src);
int len = src.length - padLength;
return new Uint8List(len)..setRange(0, len, src);
}
static String encrypt(String password, String plaintext,
{String mode = CBC_MODE}) {
String salt = toASCII(SALT);
Uint8List derivedKey = deriveKey(password, salt: salt);
KeyParameter keyParam = new KeyParameter(derivedKey);
BlockCipher aes = new AESFastEngine();
var ivStr = toASCII(INITIAL_VECTOR);
Uint8List iv =
createUint8ListFromString(ivStr);
BlockCipher cipher;
ParametersWithIV params = new ParametersWithIV(keyParam, iv);
switch (mode) {
case CBC_MODE:
cipher = new CBCBlockCipher(aes);
break;
case CFB_MODE:
cipher = new CFBBlockCipher(aes, aes.blockSize);
break;
default:
throw new ArgumentError('incorrect value of the "mode" parameter');
break;
}
cipher.init(true, params);
Uint8List textBytes = createUint8ListFromString(plaintext);
Uint8List paddedText = pad(textBytes, aes.blockSize);
Uint8List cipherBytes = _processBlocks(cipher, paddedText);
return base64.encode(cipherBytes);
}
static String decrypt(String password, String ciphertext,
{String mode = CBC_MODE}) {
String salt = toASCII(SALT);
Uint8List derivedKey = deriveKey(password, salt: salt);
KeyParameter keyParam = new KeyParameter(derivedKey);
BlockCipher aes = new AESFastEngine();
var ivStr = toASCII(INITIAL_VECTOR);
Uint8List iv = createUint8ListFromString(ivStr);
Uint8List cipherBytesFromEncode = base64.decode(ciphertext);
Uint8List cipherIvBytes =
new Uint8List(cipherBytesFromEncode.length + iv.length)
..setAll(0, iv)
..setAll(iv.length, cipherBytesFromEncode);
BlockCipher cipher;
ParametersWithIV params = new ParametersWithIV(keyParam, iv);
switch (mode) {
case CBC_MODE:
cipher = new CBCBlockCipher(aes);
break;
case CFB_MODE:
cipher = new CFBBlockCipher(aes, aes.blockSize);
break;
default:
throw new ArgumentError('incorrect value of the "mode" parameter');
break;
}
cipher.init(false, params);
int cipherLen = cipherIvBytes.length - aes.blockSize;
Uint8List cipherBytes = new Uint8List(cipherLen)
..setRange(0, cipherLen, cipherIvBytes, aes.blockSize);
Uint8List paddedText = _processBlocks(cipher, cipherBytes);
Uint8List textBytes = unpad(paddedText);
return new String.fromCharCodes(textBytes);
}
static Uint8List _processBlocks(BlockCipher cipher, Uint8List inp) {
var out = new Uint8List(inp.lengthInBytes);
for (var offset = 0; offset < inp.lengthInBytes;) {
var len = cipher.processBlock(inp, offset, out, offset);
offset += len;
}
return out;
}
}
///MARK: HELPERS
Uint8List createUint8ListFromString(String s) {
Uint8List ret = Uint8List.fromList(s.codeUnits);
return ret;
}
String toUtf8(value) {
var encoded = utf8.encode(value);
var decoded = utf8.decode(encoded);
return decoded;
}
String toASCII(value) {
var encoded = ascii.encode(value);
var decoded = ascii.decode(encoded);
return decoded;
}

The default mode of Rijndael in .Net is 128 bit block size - compatible with AES. Unless you are using a non-standard block size, prefer .Net's AesManaged.
You haven't specified which padding or mode you are using. The .Net default seems to be CBC, so we'll assume that. It's not clear whether it defaults to a certain padding mode.
(Note that you are using the key both as the IV and the key. The IV should be unique for each invocation of the encryption routine. TLDR - the way you are using AesManaged is insecure - don't use this code in real life.)
Also, you are decoding the key from a string. The key length of AES must be exactly 128 or 256 bits (or one of the more unusual ones). Unless you have chosen your string well, it is unlikely to UTF-8 encode to an exact key length. Also, by using a string you are only using bytes in the key that happen to be characters. Typically, to use a string as a password you would convert it to a key using a key derivation algorithm (e.g. PBKDF2) rather than just UTF-8 encoding it.
With all that said, if your password is exactly 16 (or 32 long) and your file is an exact multiple of 16 bytes (if it is not, you need to decide how to pad it) you should be able to decrypt it like this:
import 'dart:convert';
import 'dart:io';
import 'package:pointycastle/export.dart';
main() async {
var key = utf8.encode('abcdefghijklmnop');
var cipher = CBCBlockCipher(AESFastEngine())
..init(false, ParametersWithIV<KeyParameter>(KeyParameter(key), key));
var cipherText = await File('encryptedFile').readAsBytes();
var plainText = cipher.process(cipherText);
await File('decryptedFile').writeAsBytes(plainText, flush: true);
}

generates a key in AES padding CBC

I'm new to C #
and I generates a key
myRijndaelManaged.GenerateIV ();
myRijndaelManaged.GenerateKey ();
in Class
public string EncryptText(string plainText)
{
using (myRijndael = new RijndaelManaged())
{
RijndaelManaged myRijndaelManaged = new RijndaelManaged();
myRijndaelManaged.Mode = CipherMode.CBC;
myRijndaelManaged.Padding = PaddingMode.PKCS7;
myRijndaelManaged.GenerateIV();
myRijndaelManaged.GenerateKey();
string newKey = ByteArrayToHexString(myRijndaelManaged.Key);
string newinitVector = ByteArrayToHexString(myRijndaelManaged.IV);
byte[] encrypted = EncryptStringToBytes(plainText, myRijndael.Key, myRijndael.IV);
string encString = Convert.ToBase64String(encrypted);
return encString;
}
}
How to give the same keys in class
public string DecryptText(string encryptedString)
{
using (myRijndael = new RijndaelManaged())
{
myRijndael.Key =newKey;
myRijndael.IV = newinitVector;
myRijndael.Mode = CipherMode.CBC;
myRijndael.Padding = PaddingMode.PKCS7;
Byte[] ourEnc = Convert.FromBase64String(encryptedString);
string ourDec = DecryptStringFromBytes(ourEnc, myRijndael.Key, myRijndael.IV);
return ourDec;
}
}
When I give another key I have a problem with
System.Security.Cryptography.CryptographicException: „Padding is invalid and cannot be removed.”

Although I am no expert at encryption but it still makes sense to me. I mean, you should pass the iv and key generated to the function that decrypts.
For example:
public string DecryptText(string encryptedString, string Iv, string Key)
{
using (myRijndael = new RijndaelManaged())
{
myRijndael.Key = Key;
myRijndael.IV = Iv;
myRijndael.Mode = CipherMode.CBC;
myRijndael.Padding = PaddingMode.PKCS7;
Byte[] ourEnc = Convert.FromBase64String(encryptedString);
string ourDec = DecryptStringFromBytes(ourEnc, myRijndael.Key, myRijndael.IV);
return ourDec;
}
}
Well, I am not sure what the data types of the Iv and Key are, change them to suit yourself.

how to encrypt string in asp.net c# [duplicate]

This question already has answers here:
Encrypting & Decrypting a String in C# [duplicate]
(7 answers)
Closed 6 years ago.
public string EncryptPwd(String strString)
{
int intAscii;
string strEncryPwd = "";
for (int intIndex = 0; intIndex < strString.ToString().Length; intIndex++)
{
intAscii = (int)char.Parse(strString.ToString().Substring(intIndex, 1));
intAscii = intAscii + 5;
strEncryPwd += (char)intAscii;
}
return strEncryPwd;
}
This is my code.Please suggest me it is right way or not.

you can use this code:
Encrypt string with password:
public static string EncryptString(string Message, string Passphrase)
{
byte[] Results;
System.Text.UTF8Encoding UTF8 = new System.Text.UTF8Encoding();
MD5CryptoServiceProvider HashProvider = new MD5CryptoServiceProvider();
byte[] TDESKey = HashProvider.ComputeHash(UTF8.GetBytes(Passphrase));
TripleDESCryptoServiceProvider TDESAlgorithm = new TripleDESCryptoServiceProvider();
TDESAlgorithm.Key = TDESKey;
TDESAlgorithm.Mode = CipherMode.ECB;
TDESAlgorithm.Padding = PaddingMode.PKCS7;
byte[] DataToEncrypt = UTF8.GetBytes(Message);
try
{
ICryptoTransform Encryptor = TDESAlgorithm.CreateEncryptor();
Results = Encryptor.TransformFinalBlock(DataToEncrypt, 0, DataToEncrypt.Length);
}
finally
{
TDESAlgorithm.Clear();
HashProvider.Clear();
}
return Convert.ToBase64String(Results);
}
and Decrypt String with password:
public static string DecryptString(string Message, string Passphrase)
{
byte[] Results;
System.Text.UTF8Encoding UTF8 = new System.Text.UTF8Encoding();
MD5CryptoServiceProvider HashProvider = new MD5CryptoServiceProvider();
byte[] TDESKey = HashProvider.ComputeHash(UTF8.GetBytes(Passphrase));
TripleDESCryptoServiceProvider TDESAlgorithm = new TripleDESCryptoServiceProvider();
TDESAlgorithm.Key = TDESKey;
TDESAlgorithm.Mode = CipherMode.ECB;
TDESAlgorithm.Padding = PaddingMode.PKCS7;
byte[] DataToDecrypt = Convert.FromBase64String(Message);
// Step 5. Bat dau giai ma chuoi
try
{
ICryptoTransform Decryptor = TDESAlgorithm.CreateDecryptor();
Results = Decryptor.TransformFinalBlock(DataToDecrypt, 0, DataToDecrypt.Length);
}
catch (Exception) { Results = DataToDecrypt; }
finally
{
TDESAlgorithm.Clear();
HashProvider.Clear();
}
return UTF8.GetString(Results);
}

Do you have a way to decrypt that? Here is another answer on SO
private static readonly UTF8Encoding Encoder = new UTF8Encoding();
public static string Encrypt(string unencrypted)
{
if (string.IsNullOrEmpty(unencrypted))
return string.Empty;
try
{
var encryptedBytes = MachineKey.Protect(Encoder.GetBytes(unencrypted));
if (encryptedBytes != null && encryptedBytes.Length > 0)
return HttpServerUtility.UrlTokenEncode(encryptedBytes);
}
catch (Exception)
{
return string.Empty;
}
return string.Empty;
}
public static string Decrypt(string encrypted)
{
if (string.IsNullOrEmpty(encrypted))
return string.Empty;
try
{
var bytes = HttpServerUtility.UrlTokenDecode(encrypted);
if (bytes != null && bytes.Length > 0)
{
var decryptedBytes = MachineKey.Unprotect(bytes);
if(decryptedBytes != null && decryptedBytes.Length > 0)
return Encoder.GetString(decryptedBytes);
}
}
catch (Exception)
{
return string.Empty;
}
return string.Empty;
}

I agree with all the previous answers (especially share pvv) but in case you really did want a Caesar Cipher (Caesar Cipher is a very weak encryption and should not be used in production), and if this is a learning exercise, then here is some code
string strString = "abcdefghijklmnopqrstuvwxyz";
string enc = String.Join("", strString.ToArray().Select(x =>(char)( 'a' + (x-'a'+5)%26)));
Console.WriteLine(enc);
Or using a for loop like you did
string strEncryPwd = "";
for (int index = 0; index < strString.ToString().Length; index++)
{
int plainChar = strString[index];
int encrypted = 'a' + (plainChar - 'a' + 5) % 26;
strEncryPwd += (char)encrypted;
}
Console.WriteLine(strEncryPwd);

zeros_Padding result different output

Why it does get wrong results?
It not pkcs7 supported by the crypto ++?
I would like to know the value of the result to be like what to do.
Iv value is equal to the supposed well-delivered.
// c# code
private byte[] _iv;
private readonly string key = "7794b12op901252bfcea66d6f0521212";
public string decrypt(string Input)
{
string str = "";
RijndaelManaged managed = new RijndaelManaged();
managed.KeySize = 128;
managed.BlockSize = 128;
managed.Mode = CipherMode.CBC;
managed.Padding = PaddingMode.Zeros;
managed.Key = Encoding.UTF8.GetBytes(this.key);
managed.IV = this._iv;
try
{
ICryptoTransform transform = managed.CreateDecryptor();
byte[] bytes = null;
using (MemoryStream stream = new MemoryStream())
{
using (CryptoStream stream2 = new CryptoStream(stream, transform, CryptoStreamMode.Write))
{
byte[] buffer = Convert.FromBase64String(Input);
stream2.Write(buffer, 0, buffer.Length);
}
bytes = stream.ToArray();
}
str = Encoding.ASCII.GetString(bytes);
}
catch (Exception)
{
}
return str;
}
public string encrypt(string Input)
{
RijndaelManaged managed = new RijndaelManaged();
managed.KeySize = 128;
managed.BlockSize = 128;
managed.Mode = CipherMode.CBC;
managed.Padding = PaddingMode.Zeros;
managed.Key = Encoding.ASCII.GetBytes(this.key);
managed.GenerateIV();
this._iv = managed.IV;
ICryptoTransform transform = managed.CreateEncryptor(managed.Key, managed.IV);
byte[] inArray = null;
using (MemoryStream stream = new MemoryStream())
{
using (CryptoStream stream2 = new CryptoStream(stream, transform, CryptoStreamMode.Write))
{
byte[] bytes = Encoding.UTF8.GetBytes(Input);
stream2.Write(bytes, 0, bytes.Length);
}
inArray = stream.ToArray();
}
return Convert.ToBase64String(inArray);
}
Below is qt5 code.
Omit details.
QT code
QString aeskey = "7794b12op901252bfcea66d6f0521212";
QString _iv;
void Cipher::GenerateIV()
{
AutoSeededRandomPool rnd;
byte iv3[AES::BLOCKSIZE];
rnd.GenerateBlock(iv3, AES::BLOCKSIZE);
QByteArray out((char*)iv3, AES::BLOCKSIZE);
_iv = out.toBase64();
}
QString Cipher::AESencrypt(QString Qstr_in)
{
string str_in = Qstr_in.toStdString();
string key = aeskey.toStdString();
GenerateIV();
string iv = _iv.toStdString();
string str_out;
CBC_Mode<AES>::Encryption encryption;
encryption.SetKeyWithIV((byte*)key.c_str(), key.length(), (byte*)iv.c_str());
StringSource encryptor(str_in, true,
new StreamTransformationFilter(encryption,
new Base64Encoder(
new StringSink(str_out)
// ,StreamTransformationFilter::PKCS_PADDING
,StreamTransformationFilter::ZEROS_PADDING
)
)
);
return QString::fromStdString(str_out);
}
QString Cipher::AESdecrypt(QString Qstr_in)
{
string str_in = Qstr_in.toStdString();
string key = aeskey.toStdString();
string iv = _iv.toStdString();
string str_out;
CBC_Mode<AES>::Decryption decryption;
decryption.SetKeyWithIV((byte*)key.c_str(), key.length(), (byte*)iv.c_str());
StringSource decryptor(str_in, true,
new Base64Decoder(
new StreamTransformationFilter(decryption,
new StringSink(str_out)
// ,StreamTransformationFilter::PKCS_PADDING
,StreamTransformationFilter::DEFAULT_PADDING
)
)
);
return QString::fromStdString(str_out);
}

I don't understand really what your question is and I can't really comment so here what I think:
ICryptoTransform transform = managed.CreateEncryptor(managed.Key, managed.IV);
ICryptoTransform transform = managed.CreateDecryptor();
Both need key and IV, or at least need to be the same....
Then you used once Rijndael then AES. You could use AES in you C# too.

A couple things jump out... In C# code, you do this:
private readonly string key = "7794b12op901252bfcea66d6f0521212";
...
managed.Key = Encoding.UTF8.GetBytes(this.key);
In Crypto++ code, you do this:
QString aeskey = "7794b12op901252bfcea66d6f0521212";
...
string key = aeskey.toStdString();
You need to HexDecode the string in Crypto++.
Also, GenerateIV Base64 encodes on the Qt side of things:
AutoSeededRandomPool rnd;
byte iv3[AES::BLOCKSIZE];
rnd.GenerateBlock(iv3, AES::BLOCKSIZE);
QByteArray out((char*)iv3, AES::BLOCKSIZE);
_iv = out.toBase64();
But C# uses a byte[] (presumably not Base64 encoded):
private byte[] _iv;