Now outputs output.txt

rad-be-damned/chall.yaml

@@ -1,22 +1,17 @@
 name: rad-be-damned
 categories: 
   - crypto
-value: 100
+value: 125
 flag: 
     file: ./flag.txt
 description: |
   My friend seems to be communicating something but I can't make out anything. 
   Why do we live so close to Chernobyl anyways?
-
-  (Each letter is encoded with CRC-4-ITU)
 hints:
-  - What can CRCs also do besides error detection?
+  - Encoded with CRC (Cyclic Redundancy Checks)
 files:
-  - src: ./flag_gen.py
-deploy:
-  nc:
-    build: .
-    expose: 1337/tcp
+  - src: ./message.py
+  - src: ./output.txt
 authors:
   - Nikhil
 visible: true

rad-be-damned/message.py

@@ -0,0 +1,40 @@
+import random
+def find_leftmost_set_bit(plaintext):
+    pos = 0
+    while plaintext > 0:
+        plaintext = plaintext >> 1
+        pos += 1
+    return pos
+
+def encrypt(plaintext: str):
+    enc_plaintext = ""
+
+    for letter in plaintext:
+        cp = int("10011", 2)
+        cp_length = cp.bit_length()
+        bin_letter, rem = ord(letter), ord(letter) * 2**(cp_length - 1)
+        while (rem.bit_length() >= cp_length):
+            first_pos = find_leftmost_set_bit(rem)
+            rem = rem ^ (cp << (first_pos - cp_length))
+        enc_plaintext += format(bin_letter, "08b") + format(rem, "0" + f"{cp_length - 1}" + "b")
+
+    return enc_plaintext
+
+def rad(text: str):
+    corrupted_str = ""
+    for ind in range(0, len(text), 12):
+        bit_mask = 2 ** (random.randint(0, 11))
+        snippet = int(text[ind : ind + 12], base = 2)
+        rad_str = snippet ^ bit_mask
+        corrupted_str += format(rad_str, "012b")
+    return corrupted_str
+
+def main():
+    with open('flag.txt') as f:
+        plaintext = f.read().strip()
+    enc_plaintext = encrypt(plaintext)
+    cor_text = rad(enc_plaintext)
+    print(cor_text)
+
+if __name__ == '__main__':
+    main()

rad-be-damned/output.txt

@@ -0,0 +1 @@
+011000001011010000111000011000111110011000111100011101001100001001100111011111110110011110010100011100010111011011111001010011011011010100011010001010011110010110010000001110111010001000011100011100011100010011111101010101101011110000110010001101100011011010100011001001010010001011011111011110000010001101100110010000110011011101110101010010111000011100011001010100011001001000111000001101010001011000100111010011000001011100011111111101010111010001001000001101000000001101011100010101101010101011011110011010100010010010010011010101010101010000010000001011011100011000011010010000111110001110011111011100011101010110001010010100100111001110011100011010101000011000101010001000101001001100011101111101100010010011100000010101111010011101101000011100100101001001000001010001111111010001001101111110100101011111001100