Rating: 4.0
# Izzy
**category:** reverse
**points:** 66
**solves:** 77
## Description
Izzy was writing a novel based on Mayan culture. Will Tom finish her book so that she could rest in peace?
## Solution
The two files we have are :
command.sh:
```bash
#!/bin/bash
export i=99; grep -o . <<< cat flag.txt| while read letter; do i=$((i+1)); printf '%02x' "$(($(python3 -c "import os;import decimal; import time; decimal.getcontext().prec = 2992; index=int(os.environ.get('i')); x = str(decimal.Decimal(1) / decimal.Decimal((1010 - int(time.strftime('%m')))*1000 +1))[2:]; print(int(x[3*index:3*index+3]))") ^ $(printf '%#x\n' '"'$letter)))">>result.txt; done;
```
and result.txt:
```
2855140337590c3434040c5b411346492b3113430c11254a49220a17b3def0b3b0e1f2b7d7bdfdb8%
```
command.sh execute the following python code :
```python
import os;
import decimal;
import time;
decimal.getcontext().prec = 2992;
for index in range(100,140):
x = str(decimal.Decimal(1) / decimal.Decimal((1010 - int(time.strftime('%m')))*1000 +1))[2:];
print(int(x[3*index:3*index+3]))
```
and xor it with the letter.
I made a simple script to get the flag from result.txt:
```python
import os;
import decimal;
import time;
with open("result.txt","r") as f:
content = f.read()
content = bytes.fromhex(content)
flag = ""
decimal.getcontext().prec = 2992;
for index in range(100,140):
x = str(decimal.Decimal(1) / decimal.Decimal((1010 - int(time.strftime('%m')))*1000 +1))[2:];
flag += chr(int(x[3*index:3*index+3])^content[index-100])
print(flag) -----------
```
when I run it :
```
$ python decode.py
L0rd_0f_Xib41b4:_De4th_15_th3_r04dt0_4w3
```
The flag is **ASIS{L0rd_0f_Xib41b4:_De4th_15_th3_r04dt0_4w3}**
