There all I have a java software that I just built. I am trying to secure this software. The Java Desktop software communicates with Asp.net Core web api server.
I have a java AES encryption that I am using to encrypt my license key for my java software to prevent people for cracking my encryption algorithm. My problem now is I need to translate that same encryption process for .NETCore. So what ever is encrypted
in java can be deencrypted in Asp.net core c#.
I have a code for c# AES encryption but I would paste it cos there is a part that gets me confused in it. The part of encryption keys in my java code, I dont know how to make it uniform to my c# code. I would paste both codes below.
class AESEncryption
{
static void EncryptAesManaged(string raw)
{
string test = "asdfasdf";
try
{
// Create Aes that generates a new key and initialization vector (IV).
// Same key must be used in encryption and decryption
using (AesManaged aes = new AesManaged())
{
// Encrypt string
byte[] encrypted = Encrypt(raw, aes.Key, aes.IV);
// Print encrypted string
Console.WriteLine($"Encrypted data: {System.Text.Encoding.UTF8.GetString(encrypted)}");
// Decrypt the bytes to a string.
string decrypted = Decrypt(encrypted, aes.Key, aes.IV);
// Print decrypted string. It should be same as raw data
Console.WriteLine($"Decrypted data: {decrypted}");
}
}
catch (Exception exp)
{
Console.WriteLine(exp.Message);
}
Console.ReadKey();
}
static byte[] Encrypt(string plainText, byte[] Key, byte[] IV)
{
byte[] encrypted;
// Create a new AesManaged.
using (AesManaged aes = new AesManaged())
{
// Create encryptor
ICryptoTransform encryptor = aes.CreateEncryptor(Key, IV);
// Create MemoryStream
using (MemoryStream ms = new MemoryStream())
{
// Create crypto stream using the CryptoStream class. This class is the key to encryption
// and encrypts and decrypts data from any given stream. In this case, we will pass a memory stream
// to encrypt
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
// Create StreamWriter and write data to a stream
using (StreamWriter sw = new StreamWriter(cs))
sw.Write(plainText);
encrypted = ms.ToArray();
}
}
}
// Return encrypted data
return encrypted;
}
static string Decrypt(byte[] cipherText, byte[] Key, byte[] IV)
{
string plaintext = null;
// Create AesManaged
using (AesManaged aes = new AesManaged())
{
// Create a decryptor
ICryptoTransform decryptor = aes.CreateDecryptor(Key, IV);
// Create the streams used for decryption.
using (MemoryStream ms = new MemoryStream(cipherText))
{
// Create crypto stream
using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
{
// Read crypto stream
using (StreamReader reader = new StreamReader(cs))
plaintext = reader.ReadToEnd();
}
}
}
return plaintext;
}
}
So my confusion is how do I create an equivalent of
setKey(String myKey)
java method in c# so that both encryption would be the same
So I modified my c# code. I would paste my modification. But the encrypted strings are still different. The java one seems to be perfect but c# gives me some funy lookin strings.
class AESEncryption
{
static byte[] keybytes = new byte[16];
public static void setSecretkeys(string keyvalue)
{
byte[] bytes = Encoding.Default.GetBytes(keyvalue);
keyvalue = Encoding.UTF8.GetString(bytes);
byte[] result;
SHA1 shaM = new SHA1Managed();
result = shaM.ComputeHash(bytes);
Array.Copy(result, keybytes, 16);
Console.WriteLine("This is the encryption key " + Encoding.UTF8.GetString(keybytes));
}
public static string Encrypt(string plainText,string keyValue )//byte[] Key, byte[] IV
{
byte[] encrypted;
setSecretkeys(keyValue);
System.Text.UTF8Encoding UTF8 = new System.Text.UTF8Encoding();
// Create a new AesManaged.
using (AesManaged aes = new AesManaged())
{
aes.Key = keybytes; //UTF8.GetBytes(keyValue);
aes.Mode = CipherMode.ECB;
aes.Padding = PaddingMode.PKCS7;
// Create encryptor
ICryptoTransform encryptor = aes.CreateEncryptor(); //Key, IV
// Create MemoryStream
using (MemoryStream ms = new MemoryStream())
{
// Create crypto stream using the CryptoStream class. This class is the key to encryption
// and encrypts and decrypts data from any given stream. In this case, we will pass a memory stream
// to encrypt
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
// Create StreamWriter and write data to a stream
using (StreamWriter sw = new StreamWriter(cs))
sw.Write(plainText);
encrypted = ms.ToArray();
}
}
}
// Return encrypted data
return System.Text.Encoding.UTF8.GetString(encrypted);
// return ByteArrayToHexString(encrypted);
// return encrypted;
}
}
I more concerned at the encryption for now
I would paste below string I used to test and the key so you all see .
TEST VALUES BELOW
String to encrypt: first
Encrypted string: key
JAVA OUTPUT
ENCRYPTED RESULT BELOW
Encrypted key pi8iJb9wv6zLx/HvKjl4Ng==
Encrypted string jQsH/TZxvKKn2TPVfHaTqQ==
C# OUTPUT
Encryption key ?/"%?p??????*9x6
Encrypted string ?[p]?6q????3?|v??
It obvoius that the c# format is not same with the java format but I thought I have converted string to base64 why is it still showing like this. Please anyone help me.
Member
98 Points
326 Posts
Doing AES Encryption in C#
Jul 11, 2019 03:54 PM|InspiredJide|LINK
There all I have a java software that I just built. I am trying to secure this software. The Java Desktop software communicates with Asp.net Core web api server.
I have a java AES encryption that I am using to encrypt my license key for my java software to prevent people for cracking my encryption algorithm. My problem now is I need to translate that same encryption process for .NETCore. So what ever is encrypted in java can be deencrypted in Asp.net core c#.
I have a code for c# AES encryption but I would paste it cos there is a part that gets me confused in it. The part of encryption keys in my java code, I dont know how to make it uniform to my c# code. I would paste both codes below.
public class AES { private static SecretKeySpec secretKey; private static byte[] key; public static void setKey(String myKey) { MessageDigest sha = null; try { key = myKey.getBytes("UTF-8"); sha = MessageDigest.getInstance("SHA-1"); key = sha.digest(key); key = Arrays.copyOf(key, 16); secretKey = new SecretKeySpec(key, "AES"); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } public static String encrypt(String strToEncrypt, String secret) { try { setKey(secret); Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, secretKey); return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes("UTF-8"))); } catch (Exception e) { System.out.println("Error while encrypting: " + e.toString()); } return null; } public static String decrypt(String strToDecrypt, String secret) { try { setKey(secret); Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING"); cipher.init(Cipher.DECRYPT_MODE, secretKey); return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt))); } catch (Exception e) { System.out.println("Error while decrypting: " + e.toString()); } return null; } }MY C# code below
class AESEncryption { static void EncryptAesManaged(string raw) { string test = "asdfasdf"; try { // Create Aes that generates a new key and initialization vector (IV). // Same key must be used in encryption and decryption using (AesManaged aes = new AesManaged()) { // Encrypt string byte[] encrypted = Encrypt(raw, aes.Key, aes.IV); // Print encrypted string Console.WriteLine($"Encrypted data: {System.Text.Encoding.UTF8.GetString(encrypted)}"); // Decrypt the bytes to a string. string decrypted = Decrypt(encrypted, aes.Key, aes.IV); // Print decrypted string. It should be same as raw data Console.WriteLine($"Decrypted data: {decrypted}"); } } catch (Exception exp) { Console.WriteLine(exp.Message); } Console.ReadKey(); } static byte[] Encrypt(string plainText, byte[] Key, byte[] IV) { byte[] encrypted; // Create a new AesManaged. using (AesManaged aes = new AesManaged()) { // Create encryptor ICryptoTransform encryptor = aes.CreateEncryptor(Key, IV); // Create MemoryStream using (MemoryStream ms = new MemoryStream()) { // Create crypto stream using the CryptoStream class. This class is the key to encryption // and encrypts and decrypts data from any given stream. In this case, we will pass a memory stream // to encrypt using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write)) { // Create StreamWriter and write data to a stream using (StreamWriter sw = new StreamWriter(cs)) sw.Write(plainText); encrypted = ms.ToArray(); } } } // Return encrypted data return encrypted; } static string Decrypt(byte[] cipherText, byte[] Key, byte[] IV) { string plaintext = null; // Create AesManaged using (AesManaged aes = new AesManaged()) { // Create a decryptor ICryptoTransform decryptor = aes.CreateDecryptor(Key, IV); // Create the streams used for decryption. using (MemoryStream ms = new MemoryStream(cipherText)) { // Create crypto stream using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read)) { // Read crypto stream using (StreamReader reader = new StreamReader(cs)) plaintext = reader.ReadToEnd(); } } } return plaintext; } }So my confusion is how do I create an equivalent of
java method in c# so that both encryption would be the same
All-Star
48530 Points
18075 Posts
Re: Doing AES Encryption in C#
Jul 11, 2019 05:09 PM|PatriceSc|LINK
Hi,
From a seach it seems to compute a hash so it would be basically the same than https://docs.microsoft.com/en-us/dotnet/api/system.security.cryptography.sha1managed?view=netframework-4.8
Not sure if you can test a string and show maybe the base64 output you get so that one could try the same and see if it works.
Member
98 Points
326 Posts
Re: Doing AES Encryption in C#
Jul 11, 2019 05:29 PM|InspiredJide|LINK
thanks I would try it out
Member
98 Points
326 Posts
Re: Doing AES Encryption in C#
Jul 12, 2019 07:27 AM|InspiredJide|LINK
So I modified my c# code. I would paste my modification. But the encrypted strings are still different. The java one seems to be perfect but c# gives me some funy lookin strings.
class AESEncryption { static byte[] keybytes = new byte[16]; public static void setSecretkeys(string keyvalue) { byte[] bytes = Encoding.Default.GetBytes(keyvalue); keyvalue = Encoding.UTF8.GetString(bytes); byte[] result; SHA1 shaM = new SHA1Managed(); result = shaM.ComputeHash(bytes); Array.Copy(result, keybytes, 16); Console.WriteLine("This is the encryption key " + Encoding.UTF8.GetString(keybytes)); } public static string Encrypt(string plainText,string keyValue )//byte[] Key, byte[] IV { byte[] encrypted; setSecretkeys(keyValue); System.Text.UTF8Encoding UTF8 = new System.Text.UTF8Encoding(); // Create a new AesManaged. using (AesManaged aes = new AesManaged()) { aes.Key = keybytes; //UTF8.GetBytes(keyValue); aes.Mode = CipherMode.ECB; aes.Padding = PaddingMode.PKCS7; // Create encryptor ICryptoTransform encryptor = aes.CreateEncryptor(); //Key, IV // Create MemoryStream using (MemoryStream ms = new MemoryStream()) { // Create crypto stream using the CryptoStream class. This class is the key to encryption // and encrypts and decrypts data from any given stream. In this case, we will pass a memory stream // to encrypt using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write)) { // Create StreamWriter and write data to a stream using (StreamWriter sw = new StreamWriter(cs)) sw.Write(plainText); encrypted = ms.ToArray(); } } } // Return encrypted data return System.Text.Encoding.UTF8.GetString(encrypted); // return ByteArrayToHexString(encrypted); // return encrypted; } }I more concerned at the encryption for now
I would paste below string I used to test and the key so you all see .
TEST VALUES BELOW
String to encrypt: first
Encrypted string: key
JAVA OUTPUT
ENCRYPTED RESULT BELOW
Encrypted key pi8iJb9wv6zLx/HvKjl4Ng==
Encrypted string jQsH/TZxvKKn2TPVfHaTqQ==
C# OUTPUT
Encryption key ?/"%?p??????*9x6
Encrypted string ?[p]?6q????3?|v??
It obvoius that the c# format is not same with the java format but I thought I have converted string to base64 why is it still showing like this. Please anyone help me.
Thanks alot.
All-Star
48530 Points
18075 Posts
Re: Doing AES Encryption in C#
Jul 12, 2019 07:40 AM|PatriceSc|LINK
For now you are missing the base64 encoding done on the Java side to show those binary values using printable characters.
Add https://docs.microsoft.com/en-us/dotnet/api/system.convert.tobase64string?view=netframework-4.8 calls to show base64 strings as well. If it still doesn't match I'll give this a closer look. I don't find it right now but I discussed quite recently something similar and we ended up in finding the same values
Member
98 Points
326 Posts
Re: Doing AES Encryption in C#
Jul 12, 2019 08:34 AM|InspiredJide|LINK
Dear Pat,
Thanks alot. you are the best. Immediately I added the Base64 encoding. it worked like magic. the ecryption is exactly the same boss.
Thanks alot.