From 61e8de048331078ab2a504d6e8e42be613b18a3d Mon Sep 17 00:00:00 2001
From: Bucchino Geoffrey <geoffrey.bucchino@protonmail.com>
Date: Wed, 6 Jul 2022 21:52:44 +0200
Subject: [PATCH] Add script ic

---
 ic.py | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 ic.py

diff --git a/ic.py b/ic.py
new file mode 100644
index 0000000..d722dca
--- /dev/null
+++ b/ic.py
@@ -0,0 +1,51 @@
+# coding: utf-8
+
+from argparse import ArgumentParser
+from unidecode import unidecode
+from re import sub
+
+
+def checkArguments():
+    args = ArgumentParser(description='Cryptanalyst')
+    args.add_argument('-f', '--filename', help='Text to analyze')
+    return args.parse_args()
+
+def main():
+	args = checkArguments()
+
+	# Read file	
+	dataFile = str()
+	with open(args.filename, 'r') as f:
+		data = f.readlines()
+
+		for d in data:
+			u = unidecode(d.lower(), 'utf-8')
+			dataFile += sub(r'[^a-z]', '', u)
+
+	# Get number of letters
+	totalLetters = 0
+	for letter in dataFile:
+		totalLetters += 1
+
+	counts = []
+
+	for i in range (0, 26):
+		counts.append(0)
+
+	# Count the number of letter in our text	
+	letterToAscii = ord('a') # Get the ASCII code
+	for i in dataFile:
+		l = ord(i) - letterToAscii
+		if l >= 0 and l <= 26:
+			counts[l] += 1
+
+	# Get the sum
+	sum = 0
+	for i in range (0, 26):
+		sum += counts[i] * (counts[i] - 1)
+
+	ic = sum / (totalLetters * (totalLetters - 1))
+	print(f"Index of coincidence: {ic}")
+	
+if __name__ == "__main__":
+	main()