decrypting question

[monsieur_jj]

Hi all, I have this c# decrypting code:

public static string Decrypt(string cipherString, bool useHashing)
{
byte[] keyArray;
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)
        {
            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.CreateDecryptor();
        byte\[\] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
                    
        tdes.Clear();
        return UTF8Encoding.UTF8.GetString(resultArray);
    }

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

[Lost User]

Hello again JayJay, I have written a sample for you. It doesn't get any better than this.

#include "stdafx.h"
#include <windows.h>
#include <Wincrypt.h>
#include <assert.h>

#pragma comment(lib, "crypt32.lib")

LPTSTR Base64Decode(LPCTSTR lpData, DWORD dwSize)
{
	DWORD dwResult = 0;
	if(CryptStringToBinary(lpData, dwSize, CRYPT_STRING_BASE64, NULL, &dwResult,NULL,NULL))
	{
		LPTSTR lpszBase64Decoded = new TCHAR[dwResult+(sizeof(TCHAR) * 2)];
		memset(lpszBase64Decoded,0,dwResult);
		if(CryptStringToBinary(lpData, dwSize, CRYPT_STRING_BASE64,(BYTE *)lpszBase64Decoded, &dwResult,NULL,NULL))
		{
			*(LPWORD)(lpszBase64Decoded + (dwResult / sizeof(TCHAR))) = 0;

			return lpszBase64Decoded;
		}
	}
	return NULL;
}

LPTSTR Base64Encode(LPCBYTE lpData, DWORD dwSize, BOOL bStripCRLF)
{
	DWORD dwResult = 0;
	if(CryptBinaryToString(lpData, dwSize, CRYPT_STRING_BASE64, NULL, &dwResult))
	{
		LPTSTR lpszBase64 = new TCHAR[dwResult];
		if(CryptBinaryToString(lpData, dwSize, CRYPT_STRING_BASE64, lpszBase64, &dwResult))
		{
			TCHAR pByteLF = *(LPWORD)(lpszBase64 + dwResult -1);
			TCHAR pByteCR = *(LPWORD)(lpszBase64 + dwResult -2);
			if(pByteCR == 0x0D && pByteLF == 0x0A)
			{
				*(LPWORD)(lpszBase64 + dwResult -2) = 0;
			}
			return lpszBase64;
		}
	}
	return NULL;
}

DWORD TripleDESencrypt(TCHAR *plaintext,DWORD ptlen,TCHAR *passwd,DWORD pwlen,TCHAR *cyphertext,DWORD *ctlen)
{
	HCRYPTPROV hProv;
	HCRYPTHASH hHash;
	HCRYPTKEY hKey;
	DWORD dwSizeNeeded =0;
	DWORD sz =0;

	CryptAcquireContext(&hProv,NULL,MS_STRONG_PROV,PROV_RSA_FULL,0);
	CryptCreateHash(hProv,CALG_MD5,0,0,&hHash);
	CryptHashData(hHash,(BYTE*)passwd,pwlen,0);
	CryptDeriveKey(hProv,CALG_3DES,hHash,0,&hKey);

	if(NULL != cyphertext && 0 != ptlen)
	{
		memcpy(cyphertext,plaintext,ptlen);
		sz=*ctlen;
		*ctlen=ptlen;
	}

	if(FALSE == CryptEncrypt(hKey,NULL,1,0,(BYTE *)cyphertext,ctlen,sz))
	{
		DWORD dwError = GetLastError();
		if(ERROR_MORE_DATA == dwError)
		{
			dwSizeNeeded = *ctlen * sizeof(TCHAR);
		}
	}

	CryptDestroyKey(hKey);
	CryptDestroyHash(hHash);
	CryptReleaseContext(hProv,0);
	return dwSizeNeeded;
}

DWORD TripleDESdecrypt(TCHAR *cyphertext,DWORD ctlen,TCHAR *passwd,DWORD pwlen,TCHAR *plaintext,DWORD *ptlen)
{
	HCRYPTPROV hProv;
	HCRYPTHASH hHash;
	HCRYPTKEY hKey;
	DWORD dwSizeNeeded =0;

	CryptAcquireContext(&hProv,NULL,MS_STRONG_PROV,PROV_RSA_FULL,0);
	CryptCreateHash(hProv,CA

[monsieur_jj]

Hi David, You have been a great help so far, by the way i have tested your code it works however I still need to do some tweaking as I can't convert "Zed5OmjUWs8=" to "test" and also what is this for:

ICryptoTransform cTransform = tdes.CreateDecryptor();
byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

Thanks, Jayjay