worked on the chall

res/decoy.txt

@@ -0,0 +1,25 @@
+From: ops-team@sec.in.tum.de
+To: exam_archive@sec.in.tum.de
+Subject: [Draft Item — Secure Systems]
+
+Restricted Draft — Not Finalized
+
+Question:
+Suppose a QR code is divided into equal parts and randomly
+reordered before printing. Security is claimed because the
+order cannot be recovered without the exact permutation.  
+
+(a) Explain why relying on this hidden ordering ensures
+long-term secrecy.  
+(b) Would the presence of alignment markers or error
+correction change this conclusion? Justify briefly.  
+
+Solution (Internal Notes Only):
+(a) The scheme is secure since without the original order,
+the data is mathematically unrecoverable; no structure
+leaks to the adversary.  
+(b) Alignment markers and redundancy do not help attackers,
+because the scrambling completely destroys any visible
+pattern, leaving only random noise.  
+
+Verification Token: h4tum{fake_fake_fake_flag]

res/mosaic_secret_message

@@ -0,0 +1,24 @@
+From: hochspezialisiert@sec.in.tum.de
+To: itsec_examdraft@sec.in.tum.de
+Subject: [Draft Question — Cryptography]
+
+Confidential (ONLY FOR AUTHORIZED PERSONNEL)
+
+Question:
+Consider a toy "QR-encryption" scheme where a message is encoded into
+a QR code and then randomized by permuting its tiles with a secret seed.
+
+(a) Under ideal assumptions, explain why this scheme could satisfy
+Kerckhoffs’ principle.  
+(b) Now assume an attacker can test permutations against the QR format
+(find patterns, error correction, alignment markers). Why does this
+reduce the effective security of the scheme?  
+
+Solution (DO NOT DISTRIBUTE):
+(a) If the algorithm is known and the seed remains secret, only the
+seed determines security → aligns with Kerckhoffs’ principle.  
+(b) QR codes have strong structural redundancy (finder patterns,
+error correction). This gives the attacker an oracle to prune wrong
+seeds quickly → brute force feasible.  
+
+Verification Token: 

res/secret_message.txt

@@ -0,0 +1,4 @@
+Wow you solved the challenge!
+Meet us at our booth we really want to get in touch with you :D
+
+Show us the flag: