feat: add magic-byte challenge

magic-byte/README.md

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+# Magic Byte
+
+## Text
+
+Hi! I encrypted my flag with some awesome magic. ... Lore ... Lore ...
+Figure it out :)
+
+## Files
+
+magic_byte.txt
+
+## How to Deploy
+
+N/A

magic-byte/SOLUTION.md

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+## Difficulty
+
+Easy, because it is easy.
+
+## Category
+
+Crypto
+
+## How To Solve
+
+Just bruteforce the magic byte, xoring the ciphertext with the byte.
+
+## Flag
+
+IGCTF{hello_flag!}

magic-byte/create_magic_byte.py

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+magic = 0xCC
+flag = "IGCTF{hello_flag!}"
+
+def xor_string_with_byte(input_str, xor_byte):
+    # Convert the input string to bytes
+    input_bytes = input_str.encode()
+
+    # XOR each byte in the string with the given byte
+    xor_result = bytes([b ^ xor_byte for b in input_bytes])
+
+    # Convert the XOR result to a hex string
+    hex_result = xor_result.hex()
+
+    return hex_result
+
+def reverse_xor(hex_str, xor_byte):
+    # Convert the hex string back to bytes
+    xor_bytes = bytes.fromhex(hex_str)
+
+    # XOR each byte in the result with the same XOR byte
+    original_bytes = bytes([b ^ xor_byte for b in xor_bytes])
+
+    # Convert the result back to the original string
+    original_str = original_bytes.decode()
+
+    return original_str
+
+
+result = xor_string_with_byte(flag, magic)
+print(result)
+
+original = reverse_xor(result, magic)
+print(original)

magic-byte/magic_byte.txt

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+flag: 858b8f988ab7a4a9a0a0a393aaa0adabedb1