C / C++ / MFC

19-Nov-08 19:42

Hi all,

Is there a c++ version of this or at least can a c++ version of this algorithm can be made? Please advise. Can anyone give me a sample on how to use windows crypto api decryption just by inputting an encrypted string?

Thanks,
Jayjay

btw this is made of c#

public static string Decrypt(string cipherString, bool useHashing)
    {
        byte[] keyArray;
        //get the byte code of the string

        byte[] toEncryptArray = Convert.FromBase64String(cipherString);

        System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
        //Get your key from config file to open the lock!
        string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));

        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(key));
            //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(key);
         }

        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);
    }

modified on Thursday, November 20, 2008 3:28 AM

Randor 19-Nov-08 21:52

Randor

19-Nov-08 21:52

Bonjour JayJay,

Yes that function can be implemented in C++ using Microsoft Cryptographic Service Providers.[^] From looking at the source code you have provided it appears that the function works as follows:

1.) Function is passed a base64 encoded bytes and a boolean.
2.) Decode base64 encoded bytes to a byte array.
3.) Open a "settings reader" and retrieve a key/pair value from key 'SecurityKey'.
4.) if useHashing boolean is true then create a MD5 hash from the "SecurityKey"value.
5.) if useHashing boolean is false then cast the "SecurityKey"value to a UTF8 encoded unicode string.
6.) Decrypt the byte array using the 'Security' key with TripleDES algorithm.

You should research the following funtions from the Microsoft Cryptographic Service.

For Initializing Microsoft Cryptographic Service Providers:
CryptAcquireContext Function[^]

For base64 decoding:
CryptBinaryToString Function
[^]

For computing MD5 hash:
CryptCreateHash Function[^]
CryptDestroyHash Function[^]

For TripleDES:
CryptDeriveKey Function[^]
CryptDecrypt Function[^]
CryptDestroyKey Function[^]

For Releasing Microsoft Cryptographic Service Providers:
CryptReleaseContext Function[^]

Here are some samples:
Encoding and Decoding a Hashed Message[^]
Example C Program: Encoding and Decoding Data[^]

Some sample code from CodeGuru:
http://www.codeguru.com/forum/showthread.php?threadid=464785[^]

Hope it helps!
-David Delaune

monsieur_jj19-Nov-08 22:09

19-Nov-08 22:09

Hi Randor,

Thanks btw this is the encrypt code from where the string passed is derived:

public static string Encrypt(string toEncrypt, bool useHashing)
       {
           byte[] keyArray;
           byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

           System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
           // Get the key from config file
           string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));
           //System.Windows.Forms.MessageBox.Show(key);
           if (useHashing)
           {
               MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
               keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
               hashmd5.Clear();
           }
           else
               keyArray = UTF8Encoding.UTF8.GetBytes(key);

           TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
           tdes.Key = keyArray;
           tdes.Mode = CipherMode.ECB;
           tdes.Padding = PaddingMode.PKCS7;

           ICryptoTransform cTransform = tdes.CreateEncryptor();
           byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
           tdes.Clear();
           return Convert.ToBase64String(resultArray, 0, resultArray.Length);
       }

CPallini19-Nov-08 22:16

CPallini

19-Nov-08 22:16

Randor wrote:
Hope it helps!

If it doesn't, it is not your fault, for sure.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

monsieur_jj20-Nov-08 15:34

20-Nov-08 15:34

Bonjour David,

I am a bit confused should I use CryptBinaryToString or CryptStringtoBinary?

Thanks,
Jayjay

Re: decrypting a string question [modified]

Randor 20-Nov-08 21:58

Randor

20-Nov-08 21:58

Use CryptStringToBinary to decode from base64.
Use CryptBinaryToString to encode to base64.

Best Wishes,
-David Delaune

monsieur_jj20-Nov-08 22:09

20-Nov-08 22:09

Hi,

I did a translation test and here it is unfortunately it ends up garbage:

void ThreeDESdecrypt(unsigned char *cyphertext,unsigned long ctlen,unsigned char *passwd,unsigned long pwlen,unsigned char *plaintext,unsigned long *ptlen)
{
  HCRYPTPROV hProv = NULL;
  HCRYPTHASH hHash = NULL;
  HCRYPTKEY hKey = NULL;

  BYTE * value2 = {0};
  DWORD lul_len, lul_buflen, lul_skip, lul_pflags;
  bool lb_rtn;
  BLOB lblob_data;
 // value = reinterpret_cast<const BYTE *>(cyphertext);
  TCHAR convertedStr[13];
	convertedStr[0] = ('\0');
	BYTE key1[24] = {0};

	lul_len = 13;
	lul_buflen = (lul_len * 2);
	std::string value = "Zed5OmjUWs8=";
	hProv = InitializeCrypt(); 
	bool result = CryptStringToBinary(value.c_str(), lul_len, CRYPT_STRING_BASE64, key1, &lul_buflen, &lul_skip, NULL);

  //bool result = CryptAcquireContext(&hProv,SecurityKey,NULL, PROV_RSA_FULL, CRYPT_NEWKEYSET);
  //bool result = CryptBinaryToString(value, lul_len, CRYPT_STRING_BASE64, convertedStr, &lul_buflen);
  result = CryptCreateHash(hProv,CALG_MD5,0,0,&hHash);
  result = CryptDeriveKey(hProv,CALG_3DES,hHash,0,&hKey);
  memcpy(plaintext,key1,*ptlen);
  result = CryptDecrypt(hKey,NULL,1,0,plaintext,&ctlen);
  *ptlen=ctlen;
  result = CryptDestroyKey(hKey);
  result = CryptDestroyHash(hHash);
  result = CryptReleaseContext(hProv,0);
}

int main() {
	
  HCRYPTPROV hCryptProv;// = InitializeCrypt();

  HCRYPTHASH hHash = 0;
  HCRYPTKEY hKey = 0;
  PBYTE pbBuffer = NULL;
  DWORD dwCount;

	const BYTE * value;
	DWORD lul_len, lul_buflen, lul_skip, lul_pflags, ptlen;
	bool lb_rtn;
	BLOB lblob_data;

	std::string key = "h3bmull3r";
	const std::string s = "Zed5OmjUWs8=" ;
	value = reinterpret_cast&lt;const BYTE *&gt;(s.c_str());
	int stringSize = s.size();
	TCHAR convertedStr[12];
	convertedStr[0] = ('\0');

	lul_len = s.size();
	lul_buflen = (lul_len * 2);

	//hCryptProv = InitializeCrypt();

	char CypherText[128]="Zed5OmjUWs8="; 
	char MyPassword[]="h3bmull3r"; 
	unsigned char MyString[128];
	unsigned long len1,len2,len3;

	len1=strlen(CypherText);
	len2=strlen(MyPassword);
	len3=128; //size of the cypehrtext buffer above

	memset(MyString,0,128); //clear the buffer
	len1=128; //size of the plaintext buffer
	lb_rtn = CryptBinaryToString(value, lul_len, CRYPT_STRING_BASE64, convertedStr, &amp;lul_buflen);

	ThreeDESdecrypt((unsigned char *)CypherText,len3,(unsigned char *)MyPassword,len2,(unsigned char *)MyString,&amp;len1);
return 0;
}

The bold part CryptDecrypt returns false and the plaintext is garbage, What I expect the plaintext to contain "test".
The thing is this is the code that encrypts test:

public static string Encrypt(string toEncrypt, bool useHashing)
        {
            byte[] keyArray;
            byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

            System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
            // Get the key from config file
            string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));
            //System.Windows.Forms.MessageBox.Show(key);
            if (useHashing)
            {
                MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                hashmd5.Clear();
            }
            else
                keyArray = UTF8Encoding.UTF8.GetBytes(key);

            TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
            tdes.Key = keyArray;
            tdes.Mode = CipherMode.ECB;
            tdes.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = tdes.CreateEncryptor();
            byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
            tdes.Clear();
            return Convert.ToBase64String(resultArray, 0, resultArray.Length);
        }

That is the service that sends me the encrypted string which i need to decrypt I tested "test" as my string and I get "Zed5OmjUWs8=" as the encrypted string. also the key being used as the security key is "h3bmull3r"

Please advise.

merci,
Jayjay

modified on Friday, November 21, 2008 4:59 AM

CPallini19-Nov-08 21:59

CPallini

19-Nov-08 21:59

monsieur_jj wrote:
Is there a c++ version of this

Possibly, yes.

monsieur_jj wrote:
or at least can a c++ version of this algorithm can be made?

This for sure, even the C# one is, at the end, done in C++. Roll eyes | :rolleyes:

Reference about Crypto API here. There are also articles about, here at CodeProject [^].

Smile | :)

monsieur_jj20-Nov-08 22:05

Modifying one cell in a CListCtrl

20-Nov-08 22:05

message deleted

sunny_vc19-Nov-08 18:58

sunny_vc

19-Nov-08 18:58

Hi all,
I am using CListCtrl with Report view in my module.
I have 4 columns in it.
I want to change only a particular cell in second column but not the
entire column or the row corresponding to that cell.
I am unable to do it properly with InsertItem and SetItemText.I need to change the entire column or entire row if I use these functions.
How can I do it?

Regards,
Sunil Kumar

Hamid_RT19-Nov-08 20:28

Hamid_RT

19-Nov-08 20:28

Can you show your code how did you try?

Prasann Mayekar19-Nov-08 20:32

Prasann Mayekar

19-Nov-08 20:32

actually the setitemtext() works fine.
i u dont know, the subitem argument of the setitemtext() is actually the column identifier.

the first column is subitem = 0 and so on

Nishad S19-Nov-08 20:41

Nishad S

19-Nov-08 20:41

sunilkumar.d wrote:
I am unable to do it properly with InsertItem and SetItemText.

Why not SetItemText?

- NS -
[ODBaseBtn]

sunny_vc19-Nov-08 21:37

sunny_vc

19-Nov-08 21:37

Do I need to use InsertItem along with SetItemText even
to change a single cell value.?
Or directly I can use SetItemText(2, 1,"hello") to change second row 1st column?

Regards,
Sunil Kumar

Nishad S19-Nov-08 22:00

Nishad S

19-Nov-08 22:00

You cannot set a value to a cell if that row is not inserted yet.

- NS -
[ODBaseBtn]