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Equivalent C# cryptograph in react native

I am looking for a ReactNative equivalent for the following C# Crypto methods. Basically, I am calling a C# API endpoint that requires Json calls to be encrypted. Its also sending back encrypted results using the same Cryptography. The C# methods where provided by my client.
I am fairly new to ReactNative as such I have been unable to successfully reproduced the methods in ReactNative.
I have looked at similar functions online such as one highlighted here but to no avail.
I will higly appreciate your help.
C# METHODS
public string EncryptFromDataObject(string jsonString)
{
byte[] initVectorBytes = Encoding.UTF8.GetBytes(MySecret.sInitVector);
byte[] plainTextBytes = Encoding.UTF8.GetBytes(jsonString);
PasswordDeriveBytes password = new PasswordDeriveBytes(MySecret.sPassPhrase, null);
byte[] keyBytes = password.GetBytes(MySecret.iKeySize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
//string s = Convert.ToBase64String(cipherTextBytes); // base64 without padding
//s = s.PadRight(s.Length + (s.Length * 3) % 4, '='); // add padding
return Convert.ToBase64String(cipherTextBytes);
}
//Decrypt
public string DecryptToDataObject(string cipherDataObj)
{
byte[] initVectorBytes = Encoding.ASCII.GetBytes(MySecret.sInitVector);
byte[] cipherTextBytes = Convert.FromBase64String(cipherDataObj);
PasswordDeriveBytes password = new PasswordDeriveBytes(MySecret.sPassPhrase, null);
byte[] keyBytes = password.GetBytes(MySecret.iKeySize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
string jsonString = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
return jsonString;
}

I actually managed though not by using the above C# class but used the implementation here.
I managed to encrypt from C# and decrypt using ReactNative and vise-versa. The only catch is to make sure that the iv value used in ReactNative is generated is obtained from C# code.

RijndaelManaged "padding is invalid and cannot be removed"

I'm trying to create methods for very strong Rijndael 256 string encryption that I can use for passwords but I get an error saying Padding is invalid and cannot be removed. when I read the CryptoStream and get the decrypted string. Here are my encrypt and decrypt methods:
private string AES256EncryptString(string key, string plainText)
{
try
{
using (RijndaelManaged rijndael = new RijndaelManaged())
{
rijndael.KeySize = 256;
rijndael.BlockSize = 128;
rijndael.Key = Encoding.UTF8.GetBytes(key);
rijndael.GenerateIV();
rijndael.Mode = CipherMode.CBC;
rijndael.Padding = PaddingMode.PKCS7;
ICryptoTransform encryptor = rijndael.CreateEncryptor(rijndael.Key, rijndael.IV);
MemoryStream memoryStream = new MemoryStream();
memoryStream.Write(rijndael.IV, 0, rijndael.IV.Length);
CryptoStream crypoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
crypoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
crypoStream.FlushFinalBlock();
crypoStream.Close();
byte[] encryptedBytes = memoryStream.ToArray();
memoryStream.Close();
string encryptedText = Convert.ToBase64String(encryptedBytes);
return encryptedText;
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
return null;
}
}
private string AES256DecryptString(string key, string encryptedText)
{
try
{
using (RijndaelManaged rijndael = new RijndaelManaged())
{
rijndael.KeySize = 256;
rijndael.BlockSize = 128;
rijndael.Key = Encoding.UTF8.GetBytes(key);
byte[] encryptedTextBytes = Encoding.UTF8.GetBytes(encryptedText);
byte[] iv = new byte[16];
Array.Copy(encryptedTextBytes, iv, iv.Length);
rijndael.IV = iv;
rijndael.Mode = CipherMode.CBC;
rijndael.Padding = PaddingMode.PKCS7;
ICryptoTransform decryptor = rijndael.CreateDecryptor(rijndael.Key, rijndael.IV);
MemoryStream memoryStream = new MemoryStream();
byte[] encryptedTextWithoutIVBytes = new byte[encryptedTextBytes.Length - iv.Length];
Array.Copy(encryptedTextBytes, 16, encryptedTextWithoutIVBytes, 0, encryptedTextWithoutIVBytes.Length);
memoryStream.Write(encryptedTextWithoutIVBytes, 0, encryptedTextWithoutIVBytes.Length);
CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
StreamReader streamReader = new StreamReader(cryptoStream);
string decryptedText = streamReader.ReadToEnd();
cryptoStream.FlushFinalBlock();
cryptoStream.Close();
memoryStream.Close();
return decryptedText;
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
return null;
}
}
As you can see I add the initialization vector before the encrypted string before adding the encrypted bit because I know that IVs should be random and I've seen this is a good strategy to use. I make sure to remove the IV before decrypting.
Is there a way to fix this without changing the padding mode (I've seen that PKCS7 padding is very secure)?

Problems:
You should use a proper password-based KDF for passwords and similar low-entropy keys. .NET has the Rfc2898DeriveBytes (PBKDF2) class to make this relatively easy.
You are not base64 decoding your ciphertext in your decryptor. Instead of
byte[] encryptedTextBytes = Encoding.UTF8.GetBytes(encryptedText);
you should have
byte[] encryptedTextBytes = Convert.FromBase64String(encryptedText);
You need to reset the position of the MemoryStream after you populate it with ciphertext bytes. After
memoryStream.Write(encryptedTextWithoutIVBytes, 0, encryptedTextWithoutIVBytes.Length);
you need to insert
memoryStream.Seek(0, SeekOrigin.Begin);

Padding is invalid and cannot be removed in C#

I'm making a program with encryting and decrypting feature, but I have encountered Padding is invalid and cannot be removed problem.
Here are my codes:
Encrypt
public static string EncryptString(string plainText, string passPhrase)
{
byte[] initVectorBytes = Encoding.UTF8.GetBytes("pemgail9uzpgzl88");
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null);
byte[] keyBytes = password.GetBytes(256 / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
return Convert.ToBase64String(cipherTextBytes);
}
Decrypt
public static string DecryptString(string cipherText, string passPhrase)
{
byte[] initVectorBytes = Encoding.UTF8.GetBytes("pemgail9uzpgzl88");
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null);
byte[] keyBytes = password.GetBytes(256 / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
}
The process that is wrong is decrytping, at the line cryptoStream.Close.

You need to set the padding for both encryption and decryption.
symmetricKey.Padding=PaddingMode.PKCS7;
Also flush the final block when encrypting the data.
I tested the following code and it worked fine:
public static string Encrypt(string plainText, string passPhrase)
{
byte[] initVectorBytes = Encoding.UTF8.GetBytes("pemgail9uzpgzl88");
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null);
byte[] keyBytes = password.GetBytes(256 / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
string cipherText = Convert.ToBase64String(cipherTextBytes);
return cipherText;
}
public static string Decrypt(string cipherText, string passPhrase)
{
byte[] initVectorBytes = Encoding.UTF8.GetBytes("pemgail9uzpgzl88");
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null);
byte[] keyBytes = password.GetBytes(256 / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
string plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
return plainText;
}
I've set the padding for encryption and decryption, flushing the final block.
Try the code here.

Encryption method for using AES-256 symmetric algorithm (AES/ECB/PKCS7Padding) in c#

I want to encrypt a string using AES 256-bit encryption algorithm with ECB and PKCS7Padding. I had gone through many sites but none of them were suitable.
Please suggest a solution

public static string Encrypt(string PlainText, string Password,
string Salt = "Kosher", string HashAlgorithm = "SHA1",
int PasswordIterations = 2, string InitialVector = "OFRna73m*aze01xY",
int KeySize = 256)
{
if (string.IsNullOrEmpty(PlainText))
return "";
byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
byte[] SaltValueBytes = Encoding.ASCII.GetBytes(Salt);
byte[] PlainTextBytes = Encoding.UTF8.GetBytes(PlainText);
PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
RijndaelManaged SymmetricKey = new RijndaelManaged();
SymmetricKey.Mode = CipherMode.CBC;
byte[] CipherTextBytes = null;
using (ICryptoTransform Encryptor = SymmetricKey.CreateEncryptor(KeyBytes, InitialVectorBytes))
{
using (MemoryStream MemStream = new MemoryStream())
{
using (CryptoStream CryptoStream = new CryptoStream(MemStream, Encryptor, CryptoStreamMode.Write))
{
CryptoStream.Write(PlainTextBytes, 0, PlainTextBytes.Length);
CryptoStream.FlushFinalBlock();
CipherTextBytes = MemStream.ToArray();
MemStream.Close();
CryptoStream.Close();
}
}
}
SymmetricKey.Clear();
return Convert.ToBase64String(CipherTextBytes);
}
source
Note: you can change the mode by changing SymmetricKey.Mode = CipherMode.CBC;
and you can add SymmetricKey.Padding = PaddingMode.PKCS7; for padding

with bounty castle you should be able to do this :
cipher = CipherUtilities.GetCipher("AES/ECB/PKCS7");
cipher.Init(false, new KeyParameter(key));

Symmetric encryption which returns specific character set and specific length

I use this code below to encrypt and decrypt a string, but it returns a value including special characters and length of returned value is not specific.
I want to use this to generate a serial key, so is it possible to turn result to specific length and specific character set like A-Z,0-9 ?
static readonly string PasswordHash = "P##Sw0rd";
static readonly string SaltKey = "S#LT&KEY";
static readonly string VIKey = "#1B2c3D4e5F6g7H8";
public static string Encrypt(string plainText)
{
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash, Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);
var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding = PaddingMode.Zeros };
var encryptor = symmetricKey.CreateEncryptor(keyBytes, Encoding.ASCII.GetBytes(VIKey));
byte[] cipherTextBytes;
using (var memoryStream = new MemoryStream())
{
using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
{
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
cipherTextBytes = memoryStream.ToArray();
cryptoStream.Close();
}
memoryStream.Close();
}
return Convert.ToBase64String(cipherTextBytes);
}
public static string Decrypt(string encryptedText)
{
byte[] cipherTextBytes = Convert.FromBase64String(encryptedText);
byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash, Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);
var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding = PaddingMode.None };
var decryptor = symmetricKey.CreateDecryptor(keyBytes, Encoding.ASCII.GetBytes(VIKey));
var memoryStream = new MemoryStream(cipherTextBytes);
var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount).TrimEnd("\0".ToCharArray());
}

The two padding modes do not match. Especially PaddingMode.None does not make sense if your data is not block-aligned.
PaddingMode.Zeros also does not make sense because it causes the padding to be not removable.
It seems you have fiddled with settings until it seemed to work. That is very dangerous with cryptography. It is also an unsound development practice in general.