diff --git a/c3/ciphertext b/c3/ciphertext
new file mode 100755
index 0000000..6f474a4
--- /dev/null
+++ b/c3/ciphertext
@@ -0,0 +1 @@
+DLSeGAGDgBNJDQJDCFSFnRBIDjgHoDFCFtHDgJpiHtGDmMAQFnRBJKkBAsTMrsPSDDnEFCFtIbEDtDCIbFCFtHTJDKerFldbFObFCFtLBFkBAAAPFnRBJGEkerFlcPgKkImHnIlATJDKbTbFOkdNnsgbnJRMFnRBNAFkBAAAbrcbTKAkOgFpOgFpOpkBAAAAAAAiClFGIPFnRBaKliCgClFGtIBAAAAAAAOgGEkImHnIl
\ No newline at end of file
diff --git a/c3/convert.py b/c3/convert.py
new file mode 100755
index 0000000..9eadd24
--- /dev/null
+++ b/c3/convert.py
@@ -0,0 +1,16 @@
+#!/home/maxime/.pyvenv/bin/python3
+import sys
+chars = "test"
+
+lookup1 = "\n \"#()*+/1:=[]abcdefghijklmnopqrstuvwxyz"
+lookup2 = "ABCDEFGHIJKLMNOPQRSTabcdefghijklmnopqrst"
+
+out = ""
+
+prev = 0
+for char in chars:
+  cur = lookup1.index(char)
+  out += lookup2[(cur - prev) % 40]
+  prev = cur
+
+sys.stdout.write(out)
diff --git a/c3/sol.py b/c3/sol.py
new file mode 100755
index 0000000..3a582a0
--- /dev/null
+++ b/c3/sol.py
@@ -0,0 +1,19 @@
+#!/home/maxime/.pyvenv/bin/python3
+from pwn import *
+
+lookup1 = "\n \"#()*+/1:=[]abcdefghijklmnopqrstuvwxyz"
+lookup2 = "ABCDEFGHIJKLMNOPQRSTabcdefghijklmnopqrst"
+
+with open("ciphertext", 'r') as f:
+    ciphertext = f.read()
+
+out = ""
+prev = 0
+for char in ciphertext:
+    pos = lookup2.index(char)
+    out += lookup1[(pos+prev)%40]
+    prev = (pos+prev)%40
+
+print(out)
+
+