diff --git a/content/from-0-to-buffer-overflow-by-projects/episode-2-reverse-engineering-of-vigenere-cisco(reverse-engineering)-program.md b/content/from-0-to-buffer-overflow-by-projects/episode-2-guessing-source-code-(reverse-engineering)-program.md
similarity index 99%
rename from content/from-0-to-buffer-overflow-by-projects/episode-2-reverse-engineering-of-vigenere-cisco(reverse-engineering)-program.md
rename to content/from-0-to-buffer-overflow-by-projects/episode-2-guessing-source-code-(reverse-engineering)-program.md
index 8bc743d..179f22c 100644
--- a/content/from-0-to-buffer-overflow-by-projects/episode-2-reverse-engineering-of-vigenere-cisco(reverse-engineering)-program.md
+++ b/content/from-0-to-buffer-overflow-by-projects/episode-2-guessing-source-code-(reverse-engineering)-program.md
@@ -35,16 +35,6 @@ $ which packettracer
 /usr/local/bin/packettracer
 ```
 
-
-In order to redo same commands as me you could also download it from my repository
-
-```
-wget https://github.com/gogo2464/packet-tracer-linux-8.2.1.0118-archive/releases/edit/untagged-4b7b9f96a74e3408a5b2
-cd packet-tracer-linux-8.2.1.0118-disassembly
-sudo apt-get install --reinstall libxcb-xinerama0 --yes
-```
-
-
 Find the file `PacketTracer` with: `ls /opt/pt/bin`.
 
 The file `packettracer` provides running commands:
@@ -94,6 +84,14 @@ Router#
 
 In any cisco router you could run as well. It fits with the output of the program.
 
+In order to redo same commands as me you could also download it from my repository
+
+```
+wget https://github.com/gogo2464/packet-tracer-linux-8.2.1.0118-archive/releases/download/packet-tracer-linux-8.2.1.0118/pt.tar
+tar -xvf pt.tar
+cd pt.tar
+cd pt
+```
 
 ### 2.1: static analysis: looking for symbols (exercice)
 
diff --git a/content/from-0-to-crypto-by-projects/episode-2-proof-demonstration.md b/content/from-0-to-crypto-by-projects/episode-2-proof-demonstration.md
index 13f9236..dda1cda 100644
--- a/content/from-0-to-crypto-by-projects/episode-2-proof-demonstration.md
+++ b/content/from-0-to-crypto-by-projects/episode-2-proof-demonstration.md
@@ -9,7 +9,7 @@ draft: false
 
 According to the documentation and as it is mentionned that type 7 is an hashing algorithm.
 
-A secure hash algorithm is an hash algorithm so that there does not exist a function `$$ f(enc) $$` so that `$$ f(enc) = original_plaintext $$`. 
+A secure hash algorithm is an hash algorithm so that there does not exist a function $ f(enc) $ so that $ f(enc) = original-plaintext $. 
 
 ## 1 - Analysis under mathematical thinking
 
diff --git a/themes/hello-4s3ti/layouts/_default/baseof.html b/themes/hello-4s3ti/layouts/_default/baseof.html
index 399a30b..ff3d164 100644
--- a/themes/hello-4s3ti/layouts/_default/baseof.html
+++ b/themes/hello-4s3ti/layouts/_default/baseof.html
@@ -9,7 +9,7 @@
     {{ end }}
 	
 	
-		<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.15.1/dist/katex.min.css">
+		
         <script defer src="https://cdn.jsdelivr.net/npm/katex@0.15.1/dist/katex.min.js"></script>
         <script defer src="https://cdn.jsdelivr.net/npm/katex@0.15.1/dist/contrib/auto-render.min.js" onload="renderMathInElement(document.body);"></script>
     
diff --git a/themes/hello-4s3ti/layouts/partials/head.html b/themes/hello-4s3ti/layouts/partials/head.html
index b53c9f7..0677ac1 100644
--- a/themes/hello-4s3ti/layouts/partials/head.html
+++ b/themes/hello-4s3ti/layouts/partials/head.html
@@ -96,3 +96,20 @@
 {{- if .Site.Config.Services.GoogleAnalytics.ID }}
     {{ template "_internal/google_analytics.html" . }}
 {{- end}}
+
+<!-- katex -->
+<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.16.11/dist/katex.min.css" integrity="sha384-nB0miv6/jRmo5UMMR1wu3Gz6NLsoTkbqJghGIsx//Rlm+ZU03BU6SQNC66uf4l5+" crossorigin="anonymous">
+
+<!-- The loading of KaTeX is deferred to speed up page rendering -->
+<script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.11/dist/katex.min.js" integrity="sha384-7zkQWkzuo3B5mTepMUcHkMB5jZaolc2xDwL6VFqjFALcbeS9Ggm/Yr2r3Dy4lfFg" crossorigin="anonymous"></script>
+
+<!-- To automatically render math in text elements, include the auto-render extension: -->
+<script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.11/dist/contrib/auto-render.min.js" integrity="sha384-43gviWU0YVjaDtb/GhzOouOXtZMP/7XUzwPTstBeZFe/+rCMvRwr4yROQP43s0Xk" crossorigin="anonymous"
+	onload="renderMathInElement(document.body, {
+      delimiters: [
+          {left: '$$', right: '$$', display: true},
+          {left: '\\[', right: '\\]', display: true},
+          {left: '$', right: '$', display: false},
+          {left: '\\(', right: '\\)', display: false}
+      ]
+    });"></script>
\ No newline at end of file