glacier ctf 25

2025/glacier/rev/c2/dec

@@ -0,0 +1,30 @@
+#!/usr/bin/python3
+
+import sys
+
+KEY = (
+    b"\x2B\x5F\x52\x17\x05\x56\x41\x37\x38\x75\x01\x44\x5E\x06\x6C\x27\x09"
+    b"\x50\x41\x11\x18\x78\x56\x0D\x33\x0B\x07\x4C\x58\x0B\x07\x4C\x5F\x0B"
+    b"\x0A\x40\x59\x0B\x00\x40\x55\x0B\x06"
+)
+
+def decrypt(hex_string):
+    # Convert hex dump to bytes
+    encrypted_bytes = bytes.fromhex(hex_string.replace(" ", "").replace("\n", ""))
+    
+    decrypted = []
+    key_len = len(KEY)
+    
+    # Rolling XOR Logic (matches Rust sub_D7B0)
+    for i, byte in enumerate(encrypted_bytes):
+        k = KEY[i % key_len]
+        decrypted.append(byte ^ k)
+        
+    result_bytes = bytes(decrypted)
+    
+    print(result_bytes.decode('utf-8'))
+
+if len(sys.argv) != 2:
+    print("pass decrypt text as hexstring")
+
+decrypt(sys.argv[1])