feat: add the-in-between challenge

the-in-between/README.md

@@ -0,0 +1,13 @@
+# The In-Between
+
+## Text
+
+The **In-Between** is a place neither bound by time nor shaped by space, where reality hesitates and all things flicker in a suspended breath. It is the realm of what could have been, where choices linger just beyond reach, echoing faintly in the shadows of forgotten possibilities. Here, moments stretch and dissolve like mist, and the lines between past and future blur into a strange, eternal now. Those who stumble upon it glimpse lives they never lived, choices they never made—yet cannot stay, for the In-Between is not a place to dwell, but a fleeting whisper of all that might have been.
+
+## Files
+
+values.txt
+
+## How to Deploy
+
+N/A

the-in-between/SOLUTION.md

@@ -0,0 +1,15 @@
+## Difficulty
+
+Easy, because it is easy.
+
+## Category
+
+Crypto
+
+## How To Solve
+
+See solve.py. Using XOR properties, we can easily reverse the effects of the 3 keys leading to the original flag.
+
+## Flag
+
+IGCTF{XorGratuLatIonS!}

the-in-between/solve.py

@@ -0,0 +1,10 @@
+
+def XOR(var1,var2):
+    return bytes(a^b for a,b in zip(var1, var2))
+
+KEY1 = bytes.fromhex("d6c51e2b8932bd58555d7d6ad8aef912c40eb05c1565ac6c2fea32562105b130afab825bb4a7130d")
+KEY2_3 = bytes.fromhex("827460a08cd2bc810f0124fb65c63bc2a6aeea013554bd3afbdcc5256352865af9d10058313ad615")
+Flag = bytes.fromhex("1df63ddf439b59b6281b2bf0c91d8eb116e9353373106c")
+
+Result = XOR(XOR(KEY1,KEY2_3),Flag)
+print(Result.decode('utf-8'))

the-in-between/values.txt

@@ -0,0 +1,6 @@
+It's either right xor it's wrong—no in-between.
+
+KEY1 = d6c51e2b8932bd58555d7d6ad8aef912c40eb05c1565ac6c2fea32562105b130afab825bb4a7130d
+KEY2 ^ KEY1 = 8052260e27ec61ce9ef6fd56d19532b32cbdaf860fa88ab29107023c87351c34bb2f983348be9727
+KEY2 ^ KEY3 = 827460a08cd2bc810f0124fb65c63bc2a6aeea013554bd3afbdcc5256352865af9d10058313ad615
+FLAG ^ KEY1 ^ KEY3 ^ KEY2 = 1df63ddf439b59b6281b2bf0c91d8eb116e9353373106c