---
# System prepended metadata

title: TASK 2

---

# TASK 2
# chall 1:
![](https://i.imgur.com/lLwumeC.png)
-> dựa vào kiến thức encoding của cryptohack
f_block1:
![](https://i.imgur.com/Id2hNR4.png)
f_block2:
![](https://i.imgur.com/ScTxzAF.png)
f_block3:
![](https://i.imgur.com/8IPIyyE.png)
f_block4:
![](https://i.imgur.com/Z2Tf0Sy.png)
## flag1:
shark{ascii_hexadecimal_base64_bigInterger}
## test code:
![](https://i.imgur.com/xiondMJ.png)

# chall 2:
![](https://i.imgur.com/3KS9cu5.png)
-> decode base64, hex 3 lần
![](https://i.imgur.com/dIRSNoS.png)
![](https://i.imgur.com/1CiQsvK.png)
![](https://i.imgur.com/dObykwk.png)
![](https://i.imgur.com/Xg0kybx.png)
![](https://i.imgur.com/1W4Zdyu.png)
![](https://i.imgur.com/xbviHAe.png)
## flag2:
flag = shark {H3110_MY_Fr13ND}
## test code:
![](https://i.imgur.com/K09NN9V.png)

# chall 3:
![](https://i.imgur.com/94xhih8.png)
input:
```
def xor(a: bytes, b: bytes):
    return bytes([a[i%len(a)] ^ b[i%len(b)] for i in range(max(len(a), len(b)))])

flag = b"shark{????????????????????????????}"
key = b"??????"
output = b"\x10\x1a\x18\x02\x1f\x14\x1b\x1d\x0b/<\x0e<$\x18\x1e+,\x16\x0f"
key = xor(flag, output)
print(key)
from pwn import xor
key = bytes.fromhex('63727970746f')
print(xor(output,key))
```
output:
```
b'shark{xor_Ha_Van_Cu}'
```
## flag3:
flag = shark{xor_Ha_Van_Cu}
## test code:
![](https://i.imgur.com/xFYXEkn.png)

# chall 4:
![](https://i.imgur.com/X0m3SPR.png)
-> số xui xẻo, không may mắn thường là số 13.
![](https://i.imgur.com/oh1GjoC.png)
![](https://i.imgur.com/FH9xVLs.png)
## flag4:
flag = shark{let_me_down_slowly}
## test code:
![](https://i.imgur.com/uvK2nJU.png)

# chall 5:
![](https://i.imgur.com/vvgX5h5.png)
-> lag = xor(key1,key2)
input:
```
key3 = b'7\xdc\xb2\x92\x03\x0f\xaa\x90\xd0~\xec\x17\xe3\xb1\xc6\xd8\xda\xf9L5\xd4\xc9\x19\x1a^\x1e'
key4 = b'\x91\x14\x04\xe1?\x94\x88N\xab\xbe\xc9%\x85\x12@\xa5/\xa3\x81\xdd\xb7\x97\x00\xddm\r'
key5 = b'\x04\xee\x98U \x8a,\xd5\x90\x91\xd0Gg\xaeG\x961p\xd1f\r\xf7\xf5o_\xaf'
key6 = b'\xd1NOTwjzy\x8a?\xaa\x14oe\x9e\x85\xacKh\xd1\x18\xc0\x89\xdc3\xd8\xc7VqRnpgT\x9a$\x94\x08'
from pwn import xor
key1 = xor(key3,key4)
key2 = xor(key5,key6)
print(xor(key1,key2))
```
output:
```
b'shark{tran_anh_nhat_viet_dep_trai_qua}'
```
## flag5:
flag = shark{tran_anh_nhat_viet_dep_trai_qua}
## test code:
![](https://i.imgur.com/1ESmeEa.png)

# chall 6:
![](https://i.imgur.com/nEDJC9j.png)
![](https://i.imgur.com/wAo9hj0.png)
## flag6:
flag = shark{B4BY_5H4rK_D00_D00_D00_D00}
## test code:
![](https://i.imgur.com/ppI8pMX.png)

# chall 7:
![](https://i.imgur.com/90jR2Ao.png)
Br41LL3 alphabet -> braille alphabet
![](https://i.imgur.com/a16zNGU.png)
## flag7:
flag = shark{t00_bl1nd_t0_s33}
## test code:
![](https://i.imgur.com/T04wXjO.png)
