What is it? @.@

Here is the place where I record some tactics about wargame, systems, and other security issues.


Hack This Site! - Basic 6


An encryption system has been set up, which uses an unknown algorithm to change the text given. Requirements: Persistence, some general cryptography knowledge.

Level 6

Network Security Sam has encrypted his password. The encryption system is publically available and can be accessed with this form:

Please enter a string to have it encrypted.
You have recovered his encrypted password. It is:

Decrypt the password and enter it below to advance to the next level.
  1. First, you already got the encrypted password.
  2. Then, you should find out the rules of this encryption algorithm.
    Use this ASCII Table and make your input password encrypted
    You will get 'abcd' should be stored as 'aceg', and '1234' should be stored as '1357'
  3. Finally, you got the rules of the algorithm, which the character's position in the password means how many times the character will be shifted. For example,the inputed password 'abcd'
    a is in the 0 position, a will be shifted at 0 time, a->a.
    b is in the 1 position, b will be shifted at 1 time, b->c.
    c is in the 2 position, c will be shifted at 2 times, c->e.
    d is in the 3 position, d will be shifted at 3 times, d->g, etc.
  4. After all, if you encrypt '040d6723', you will see there's the text on the page.
    Your encrypted string is: '052g:<8:'
  5. Submit the password
  6. Congratulations, you have successfully completed basic 6!