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Thread: Code for Decryption

  1. #1
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    Post Code for Decryption

    Hi Guys !

    i had a problem which i have solved but not sure why it works like this
    Import java.io.*; 
    Public class Decrypt{ 	
    Public static void main(String[] args){ 	
    Try { 	
    FileInputStream input= new FileInputStream (new file(“path/filename.enc”)); 	
    FileOutputStream output= new FileOutputStream(new File (“path/file2.txt”)); 	
     
    Boolean eof=false; 	
    int b=-1; 
    int EncryptedValue=0xD397B428; 
    int mulValue=0x41C64E6D; 
    int addValue=0x3039; 
     
    input.read(); 
    input.read();
    input.read();
    input.read();
    input.read();
    input.read();
    input.read();
    input.read();
     
    While(!eof){  
    b=input.read(); 
    if(b==-1){ 
    eof=true; 
    } Else {
    EncryptedValue=EncryptedValue*mulValue; 
    EncryptedValue=Encrypted+addValue; 
    output.write(b^magicValue); 
    System.out.println(integer.toHexString(b));
    }
    } 
    Output.close(); 
    Input.close();
    } 
    Catch(Exception e){ 
    System.out.println(e.getMessage());
    }
    }
    }

    i don't understand why i have to write
     input.read ();
    eight times to correctly decrypt the file?

    can anyone explain??

    Regards,

    Ewa


  2. #2
    Think of me.... Mr.777's Avatar
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    Default Re: Code for Decryption

    Does this program compile correctly?
    And after fixing the code, i commented all the 8 lines (input.read()) and it worked exactly similar as it worked before. I didn't find any problem.

  3. #3
    Super Moderator Norm's Avatar
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    Default Re: Code for Decryption

    The 8 read() statements read and ignore 8 bytes from the file. What are in those 8 bytes that you can ignore them?
    Do you have a definition of what each byte in the enc file contains?

  4. The Following User Says Thank You to Norm For This Useful Post:

    me_newbie (June 26th, 2012)

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