how to decrypt encrypt file without password?

Answer 1

The password is usually used as part of the encryption algorythm so is very usefull when you need to decrypt the data.

To decrypt data without the password depends on the data.
If it is encrypted text you can usually decode it over time. If it is data and you don't know what the data is supposed to look like then you will have a difficult time doing it.

Answer 2

Hello

In generally speaking, that file encryption or decryption can be done without password, by using text pattern reading methods. As you read each CHAR and convert them to unreadable format, in the same way, you have to use reverse algorithm and get the original text back. Here you don't need to use password, at all.

I don't know in which language you are working on, so here is the sample code used in c#.net 2003

Code:
=====

static void Main(string[] args)
{
//Creating a file stream
FileStream fs = new FileStream("EncryptedFile.txt",FileMode.Create,FileAccess.Write);

Console.WriteLine("Enter Some Text to be stored in encrypted file:");
String strinput = Console.ReadLine();

Byte[] bytearrayinput=ConvertStringToByteArray(strinput);

//DES instance with random key
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
//create DES Encryptor from this instance
ICryptoTransform desencrypt = des.CreateEncryptor();

//Create Crypto Stream that transforms file stream using des encryption
CryptoStream cryptostream = new CryptoStream(fs,desencrypt,CryptoStreamMode.Write);

//write out DES encrypted file
cryptostream.Write(bytearrayinput,0,bytearrayinput.Length);

cryptostream.Close();

//create file stream to read encrypted file back
FileStream fsread = new FileStream("EncryptedFile.txt",FileMode.Open,FileAccess.Read);

//create DES Decryptor from our des instance
ICryptoTransform desdecrypt = des.CreateDecryptor();

//create crypto stream set to read and do a des decryption transform on incoming bytes
CryptoStream cryptostreamDecr = new CryptoStream(fsread,desdecrypt,CryptoStreamMode.Read);
//print out the contents of the decrypted file
Console.WriteLine( (new StreamReader(cryptostreamDecr, new UnicodeEncoding())).ReadToEnd() );

Console.WriteLine ();
Console.WriteLine ("Press Enter to continue...");
Console.ReadLine();

}

Hope this helps.

Answer 3

You must have the password to decrypt and encrypt the files. That's what encryption is all about.

Answer 4

That's the beauty of encryption. Unless you have the password, the only other way is to brute force it. With a single computer and 256 bit encrytption, it can take up to, oh, about this side of forever (1000 attempts per sec will take 1.34e69 years to crack, if my math is correct)

Answer 5

YES, nothing is impossible. It may take thousands of years for super computers to crack the encryption. But history tells us that "human will" is always stronger than technology. Of course, it will not be easy. It's all about the Art of Cryptography. And we as mankind have long history(thousands of years) of cracking codes without keys. US Military cracked German Enigma and Japanese Purple Box (in 8 months) during World War II.

Answer 6

right click on that file and choose decrypt

Answer 7

write a program