diff --git a/org/binary_exploit.org b/org/binary_exploit.org
new file mode 100644
index 0000000..b6e225b
--- /dev/null
+++ b/org/binary_exploit.org
@@ -0,0 +1,71 @@
+#+TITLE: Binary Exploit Resources I Recently Trying to Learn
+#+TAGS: relearn(r)
+#+OPTIONS: toc:nil
+
+
+* resources
+** video
+[[https://youtube.com/playlist?list=PLhixgUqwRTjxglIswKp9mpkfPNfHkzyeN][Binary Exploitation / Memory Corruption by LiveOverflow]]
+** website
+*** [[https://play.picoctf.org/practice][picoCTF]]
+*** [[https://exploit.education/][exploit education]]
+
+* tools
+
+** code auditing
+[[../images/fedora_security_lab.png]]
+*** pscan
+*** rats
+*** splint
+*** flawfinder
+
+** debug
+*** gdb
+
+** reverse
+*** [[https://book.rada.re/][radare2]]
+**** iaito
+*** hopper(non-free)
+
+
+* notes on video
+** [[https://youtu.be/6jSKldt7Eqs][0x04: asm basics]]
+*** to show assembly in the source code window in gud, ~M-x gdb-display-disassembly-buffer~
+*** links
+**** https://microcorruption.com/
+** [[https://youtu.be/3NTXFUxcKPc][0x06: tools]]
+*** simple tools
+**** hexdump
+**** strings
+all printable letters
+**** objdump
+disassembler
+**** strace/ltrace
+trace sys/lib call
+*** [[https://youtu.be/mT1V7IL2FHY][0x0A: deal with numbers]]
+**** endian?
+from [[https://zh.wikipedia.org/zh-cn/%E5%AD%97%E8%8A%82%E5%BA%8F][Wikipedia]]
+[[../images/Big-Endian.svg.png ]][[../images/Little-Endian.svg.png]]
+x86 is little endian
+**** tools
+***** python
+#+BEGIN_SRC python
+  >>> int('111', 2)
+  7
+  >>> hex(123)
+  '0x7b'
+  >>> import struct
+  # https://docs.python.org/3.10/library/struct.html#format-characters
+  >>> struct.pack("<I", 0x61626364) # little endian
+  b'dcba'
+  >>> struct.pack(">I", 0x61626364) # big endian
+  b'abcd'
+#+END_SRC
+***** iex
+#+BEGIN_SRC elixir
+  iex(1)> <<0x61626364::32>>
+  "abcd"
+  iex(2)> Base.decode16("61626364")
+  {:ok, "abcd"}
+#+END_SRC
+
diff --git a/org/cheatsheet.org b/org/cheatsheet.org
index f9c08b0..66dff36 100644
--- a/org/cheatsheet.org
+++ b/org/cheatsheet.org
@@ -52,12 +52,12 @@
 
 * EMACS
 ** org-mode
-| key       | usage     |
-|-----------+-----------|
-| C-c \vbar | 创建表格  |
-| C-c C-e   | 导出 HTML |
-|           |           |
-|           |           |
+| key          | usage                      |
+|--------------+----------------------------|
+| C-c \vbar    | 创建表格                   |
+| C-c C-e      | 导出 HTML                  |
+| M-left/right | 升级(promote)/降级(demote) |
+| C-c C-x C-v  | toggle render images       |
 
 ** normal
 | key     | usage               |
@@ -69,6 +69,10 @@
 | C-x C-; | 行切换注释          |
 | C-y     | paste to minibuffer |
 
+** dired
+| key | usage  |
+| R   | rename |
+
 * Git (虽然不算editor, 但是先也放这吧)
 #+BEGIN_SRC shell
   git log --stat | perl -ne 'END { print $c } $c += $1 if /(\d+) insertions/;'
diff --git a/org/internet_collections.org b/org/internet_collections.org
index 5c548ca..ce5047d 100644
--- a/org/internet_collections.org
+++ b/org/internet_collections.org
@@ -78,6 +78,9 @@ old
 very high quality
 *** [[http://tomasp.net/commodore64][commodore64 BASIC]]
 *** [[http://tomasp.net/blog/csharp-async-gotchas.aspx][async in C#(gotchas) and F#]]
+** [[http://www.xianwaizhiyin.net/][弦外之音]]                                                     :c:lowlevel:
+** [[https://creamidea.github.io/][C-tone]]
+pretty and concise page
 
 * YouTube 收集(没有账号, 这就是我的收藏夹)
 ** Code
@@ -89,13 +92,13 @@ java bad, python slow, nvidia fuck you, vi-sual studio, C艹 sucks
 legacy
 *** [[https://youtu.be/qKA2NZ1-kx0][tsoding write cool shell in rust]]
 *** [[https://youtu.be/hmMtQe_mYr0][tsoding helloworld in c]]
-*** [[https://www.youtube.com/watch?list=RDCMUChl_NKOs1qqh_x7yJfaDpDw][Tantan 合集]]
+*** [[https://www.youtube.com/playlist?list=RDCMUChl_NKOs1qqh_x7yJfaDpDw][Tantan 合集]]
 Rust Graphics
-*** [[https://www.youtube.com/watch?list=PLGNbPb3dQJ_446PjTYQ0mCn2OGoHSKraB][build a virtual machine 合集(6/29)]]
-*** [[https://www.youtube.com/watch?list=PLSiFUSQSRYAOFwfP-aMzXJlWKVyIuWfPU][stack-based virtual machine(6 episode)]]
+*** [[https://www.youtube.com/playlist?list=PLGNbPb3dQJ_446PjTYQ0mCn2OGoHSKraB][build a virtual machine 合集(6/29)]]
+*** [[https://www.youtube.com/playlist?list=PLSiFUSQSRYAOFwfP-aMzXJlWKVyIuWfPU][stack-based virtual machine(6 episode)]]
 and [[https://youtu.be/cfPDeso3XwI][register-based(13 episode)]]
 *** [[https://youtu.be/_uAMo-bXI5g][register virtual machine in rust, with memory visualization]]
-*** [[https://www.youtube.com/watch?list=PLpM-Dvs8t0VY73ytTCQqgvgCWttV3m8LM][tsoding virtual machine in C]] , [[https://dongdigua.github.io/tsoding_bm][some notes]]
+*** [[https://www.youtube.com/playlist?list=PLpM-Dvs8t0VY73ytTCQqgvgCWttV3m8LM][tsoding virtual machine in C]] , [[https://dongdigua.github.io/tsoding_bm][some notes]]
 *** [[https://youtu.be/Fq9chEBQMFE][what if I try to malloc too much memory]]
 *** [[https://youtu.be/qF7dkrce-mQ][fireship bitcoin]]
 大概是我见过最好的讲区块链的视频了, 除了...JS 啊啊啊
@@ -110,6 +113,7 @@ and [[https://youtu.be/cfPDeso3XwI][register-based(13 episode)]]
 1:50 sexplib?
 2:00 build own irc lib
 2:14 "how many american server you have already hacked" - "I don't count them I'm sorry"
+*** [[https://youtube.be/TLa2VqcGGEQ][CVE-2021-3156 sudo]]
 
 ** Minecraft
 *** [[https://youtu.be/VKydXD6Lr20][Mojang & Minecraft 开始衰落了吗?]]