From bf106bf76d8d2142bfd4a9b70d0d543b1acb8ee3 Mon Sep 17 00:00:00 2001
From: Eggert Jung <eggert.s.jung@wischhof13.de>
Date: Sun, 22 Nov 2020 23:15:41 +0100
Subject: [PATCH 1/4] add decrypt and update encrypt

---
 src/vigenere/vig.py | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/vigenere/vig.py b/src/vigenere/vig.py
index 0391d41..7df5856 100644
--- a/src/vigenere/vig.py
+++ b/src/vigenere/vig.py
@@ -1,13 +1,16 @@
 def encrypt(key, plaintext):
-    pln_bytes = bytes(plaintext, 'UTF-8')
-    key_bytes = bytes(key, 'UTF-8')
     out=""
+    for i in range(0, len(plaintext)):
+        out = out + chr(((ord(key[i%len(key)])+ord(plaintext[i])-(0x61+0x61))%26)+0x61)
+    return out
 
-    for i in range(len(pln_bytes)):
-        pln_chr_index = pln_bytes[i] - 0x61
-        key_chr_index = key_bytes[i % len(key)] - 0x61
-        out_chr_index = (pln_chr_index + key_chr_index) % 26
-        out = out + chr(out_chr_index + 0x61)
+def decrypt(key, cipertext):
+    out=""
+    for i in range(0, len(cipertext)):
+        pln = ord(cipertext[i])-(ord(key[i%len(key)]) - 0x61)
+        if pln < 0x61:
+            pln = pln + 26
+        out = out + chr(pln)
     return out
 
 if __name__ == "__main__":
@@ -20,5 +23,15 @@ if __name__ == "__main__":
     parser.add_argument('--out', metavar='FILE')
 
     args = parser.parse_args()
+    fd = open(args.FILE, "r")
+    txt_in = fd.read()
+    txt = ""
+    for i in txt_in.lower():
+        if i.isalpha():
+            txt = txt + i
+
+    if(args.encrypt != None):
+        print(encrypt(args.encrypt, txt))
 
-print(encrypt("bbb", "test"))
+    if(args.decrypt != None):
+        print(decrypt(args.decrypt, txt))

From 8078694ee0d71c37595d9be59af42d72adab494e Mon Sep 17 00:00:00 2001
From: Eggert Jung <eggert.s.jung@wischhof13.de>
Date: Sun, 22 Nov 2020 23:56:00 +0100
Subject: [PATCH 2/4] shorten code

---
 src/vigenere/vig.py | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/src/vigenere/vig.py b/src/vigenere/vig.py
index 7df5856..f7557bb 100644
--- a/src/vigenere/vig.py
+++ b/src/vigenere/vig.py
@@ -8,9 +8,8 @@ def decrypt(key, cipertext):
     out=""
     for i in range(0, len(cipertext)):
         pln = ord(cipertext[i])-(ord(key[i%len(key)]) - 0x61)
-        if pln < 0x61:
-            pln = pln + 26
-        out = out + chr(pln)
+        pln = pln + 26 if pln < 0x61 else pln
+        out += chr(pln)
     return out
 
 if __name__ == "__main__":
@@ -21,14 +20,10 @@ if __name__ == "__main__":
     command_group.add_argument('--encrypt', metavar='KEY')
     command_group.add_argument('--decrypt', metavar='KEY')
     parser.add_argument('--out', metavar='FILE')
-
     args = parser.parse_args()
-    fd = open(args.FILE, "r")
-    txt_in = fd.read()
-    txt = ""
-    for i in txt_in.lower():
-        if i.isalpha():
-            txt = txt + i
+
+    #strip non-alphabetic chars from file and convert to lower case
+    txt = ''.join([x for x in open(args.FILE, "r").read().lower() if x.isalpha()])
 
     if(args.encrypt != None):
         print(encrypt(args.encrypt, txt))

From 7dec1c6eb9466101ac53818b389b9b7040874ea2 Mon Sep 17 00:00:00 2001
From: Eggert Jung <eggert.s.jung@wischhof13.de>
Date: Mon, 23 Nov 2020 00:15:56 +0100
Subject: [PATCH 3/4] pep up code

---
 src/vigenere/vig.py | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/vigenere/vig.py b/src/vigenere/vig.py
index f7557bb..d215bd1 100644
--- a/src/vigenere/vig.py
+++ b/src/vigenere/vig.py
@@ -1,17 +1,20 @@
 def encrypt(key, plaintext):
-    out=""
+    out = ""
     for i in range(0, len(plaintext)):
-        out = out + chr(((ord(key[i%len(key)])+ord(plaintext[i])-(0x61+0x61))%26)+0x61)
+        out += chr(((ord(key[i % len(key)]) +
+                     ord(plaintext[i]) - (2 * 0x61)) % 26)+0x61)
     return out
 
+
 def decrypt(key, cipertext):
-    out=""
+    out = ""
     for i in range(0, len(cipertext)):
-        pln = ord(cipertext[i])-(ord(key[i%len(key)]) - 0x61)
+        pln = ord(cipertext[i])-(ord(key[i % len(key)]) - 0x61)
         pln = pln + 26 if pln < 0x61 else pln
         out += chr(pln)
     return out
 
+
 if __name__ == "__main__":
     import argparse
     parser = argparse.ArgumentParser()
@@ -22,11 +25,11 @@ if __name__ == "__main__":
     parser.add_argument('--out', metavar='FILE')
     args = parser.parse_args()
 
-    #strip non-alphabetic chars from file and convert to lower case
-    txt = ''.join([x for x in open(args.FILE, "r").read().lower() if x.isalpha()])
+    # strip non-alphabetic chars from file and convert to lower case
+    t = ''.join([x for x in open(args.FILE, "r").read().lower() if x.isalpha()])
 
     if(args.encrypt != None):
-        print(encrypt(args.encrypt, txt))
+        print(encrypt(args.encrypt, t))
 
     if(args.decrypt != None):
-        print(decrypt(args.decrypt, txt))
+        print(decrypt(args.decrypt, t))

From 839c571f6ffb98171c88acd183e18d93b365f4aa Mon Sep 17 00:00:00 2001
From: Eggert Jung <eggert.s.jung@wischhof13.de>
Date: Mon, 23 Nov 2020 00:34:29 +0100
Subject: [PATCH 4/4] add file writing when using --out

---
 src/vigenere/vig.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/vigenere/vig.py b/src/vigenere/vig.py
index d215bd1..9470929 100644
--- a/src/vigenere/vig.py
+++ b/src/vigenere/vig.py
@@ -29,7 +29,12 @@ if __name__ == "__main__":
     t = ''.join([x for x in open(args.FILE, "r").read().lower() if x.isalpha()])
 
     if(args.encrypt != None):
-        print(encrypt(args.encrypt, t))
+        out = encrypt(args.encrypt, t)
 
     if(args.decrypt != None):
-        print(decrypt(args.decrypt, t))
+        out = decrypt(args.decrypt, t)
+
+    if(args.out != None):
+        open(args.out, "w").write(out)
+    else:
+        print(out)