Rating: 3.0
# Crypto Challenge
## dias skeerG tneicna - 20
### Description:
```Nothing```
### Given:
```1 File was given i) decode.me```
### Objective:
```To decrypt the text provided in "decode.me"```
### What to do:
```Decrypt the text using any cipher technique```
### Tools Required:
Text Editor
### Solution:
Step: Check file format -- success
Command: file decode.me
Output: Just a regular text file with some cipher text
Cipher Text: 554545532245{22434223_4223_42212322_55_234234313551_34553131423344}
Step: Analyze the code manually -- success
Information: 1. Since the format of the string is like "...{...}...", one can easily guess the flag is there and substitution technique is used
2. Comparing cipher text with AFFCTF{...}
3. There is no 0 in the string, maybe 0 is not included
Output: A = 55, F = 45, C = 53, T = 22
Step: Make a table consisting of A-Z with there codes -- failure
Output: A = 55
B = 54
C = 53
D = 52
E = 51
F = 50 ...
Step: Make a table consisting of A-Z with there codes without using 0 -- failure
Output: A = 55
B = 54
C = 53
D = 52
E = 51
F = 45 ...
Step: In previous step we get the code T = 21 and we cannot get a code for Z, So make another table -- success
Information: Playfair cipher uses 25 blocks for A-Z by combining I/J in a single block
Output: A = 55
B = 54
I/J = 42
Z = 11
Step: Crack the cipher simply putting the values
Output: AFFCTF{THIS_IS_JUST_A_SIMPLE_MAPPING}
### Flag:
AFFCTF{THIS_IS_JUST_A_SIMPLE_MAPPING}
