first

trabalho1/afreq.py

@@ -0,0 +1,60 @@
+frequencias = {
+    'A': 14.63,
+    'B': 1.04,
+    'C': 3.88,
+    'D': 4.99,
+    'E': 12.57,
+    'F': 1.02,
+    'G': 1.30,
+    'H': 1.28,
+    'I': 6.18,
+    'J': 0.40,
+    'K': 0.02,
+    'L': 2.78,
+    'M': 4.74,
+    'N': 5.05,
+    'O': 10.73,
+    'P': 2.52,
+    'Q': 1.20,
+    'R': 6.53,
+    'S': 7.81,
+    'T': 4.34,
+    'U': 4.63,
+    'V': 1.67,
+    'W': 0.01,
+    'X': 0.21,
+    'Y': 0.01,
+    'Z': 0.47
+}
+
+def afreq(string):
+    # determinar a frequencia de cada caractere na string
+    # comparar com a frequencia de cada caractere na lingua portuguesa
+    # calcular a diferenca entre as frequencias
+
+    str_freq = {}
+    for c in string:
+        if not c.isalnum():
+            continue
+
+        if c in str_freq:
+            str_freq[c] += 1
+        else:
+            str_freq[c] = 1
+
+    for c in str_freq:
+        if not c.isalnum():
+            continue
+
+        str_freq[c] /= len(string)
+
+    freq_sorted = dict(sorted(str_freq.items(), key=lambda item: item[1]))
+
+    possiveis_chaves = []
+    for c in frequencias:
+        for k in freq_sorted:
+            if abs(frequencias[c] - freq_sorted[k]) < 0.5:
+                possiveis_chaves.append(ord(k) - ord(c))
+
+    return possiveis_chaves
+

trabalho1/cesar.py

@@ -0,0 +1,76 @@
+import sys
+
+if len(sys.argv) != 4:
+    print("Usage: python3 cesar.py -c/-d [key] [string]")
+    sys.exit(1)
+
+encrypt = True
+if sys.argv[1] == "-d":
+    encrypt = False
+
+key = int(sys.argv[2])
+string = sys.argv[3]
+
+if not encrypt:
+    key *= -1
+
+special_letters = {
+    "ã": "a",
+    "á": "a",
+    "à": "a",
+    "é": "e",
+    "ê": "e",
+    "í": "i",
+    "ó": "o",
+    "õ": "o",
+    "ô": "o",
+    "ú": "u",
+    "ç": "c"
+}
+special_chars = {
+    " ": " ",
+    ".": ".",
+    ",": ",",
+    ";": ";",
+    ":": ":",
+    "!": "!",
+    "?": "?",
+    "(": "(",
+    ")": ")"
+}
+
+def cesar(string, key):
+    new_string = ""
+
+    for letter in string:
+        if letter in special_chars:
+            new_string += special_chars[letter]
+            continue
+
+        if letter in special_letters:
+            letter = special_letters[letter]
+
+        new_letter = ord(letter) + key
+
+        # [A-Z, a-z, 0-9]
+        if ord('0') <= ord(letter) <= ord('9'):
+            if new_letter > ord('9'):
+                new_letter += 7 # 9 + 1 = A
+            elif new_letter < ord('0'):
+                new_letter += 75 # 0 - 1 = z
+        elif letter.isupper():
+            if new_letter > ord('Z'):
+                new_letter += 6 # Z + 1 = a
+            elif new_letter < ord('A'):
+                new_letter -= 7 # A - 1 = 9
+        else:
+            if new_letter > ord('z'):
+                new_letter -= 75 # z + 1 = 0
+            elif new_letter < ord('a'):
+                new_letter -= 6 # a - 1 = Z
+
+        new_string += chr(new_letter)
+
+    return new_string
+
+print(cesar(string, key))