Prepare workshop

saison-2/sources/espionnage/bordurie/encrypt.py

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+import sys
+
+
+def rotate(x, y):
+    return (x + y) % 26
+
+
+def shift(letter, n):
+    x = ord(letter) - ord("A")
+    y = rotate(x, n)
+    return chr(ord("A") + y)
+
+
+def rot13(message):
+    message = "".join([x for x in message if x.isalpha()])
+    message = message.upper()
+    res = ""
+    for c in message:
+        res += shift(c, 13)
+    return res
+
+
+def encrypt(key, message):
+    message = "".join([x for x in message if x.isalpha()])
+    message = message.upper()
+    res = ""
+    i = 0
+    for c in message:
+        x = ord(key[i % len(key)]) - ord("A")
+        res += shift(c, x)
+        i += 1
+    return res
+
+
+def main():
+    cle = sys.argv[1]
+    message = sys.argv[2]
+    res = encrypt(cle, message)
+    print(res)
+
+
+if __name__ == "__main__":
+    main()

saison-2/sources/espionnage/bordurie/test_chiffre.py

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+def rotate(x, y):
+    return (x + y) % 26
+
+
+def shift(letter, n):
+    x = ord(letter) - ord('A')
+    y = rotate(x, n)
+    return chr(ord('A') + y)
+
+
+def rot13(message):
+    message = "".join([x for x in message if x.isalpha()])
+    message = message.upper()
+    res = ""
+    for c in message:
+        res += shift(c, 13)
+    return res
+
+
+def test_rotate():
+    assert rotate(1, 3) == 4
+    assert rotate(25, 3) == 2
+
+
+def test_shift():
+    assert shift('A', 2) == 'C'
+    assert shift('E', 2) == 'G'
+    assert shift('Y', 3) == 'B'
+
+
+def test_rot13():
+    assert rot13('hello') == 'URYYB'
+    assert rot13('URYYB') == 'HELLO'

saison-2/sources/espionnage/notes

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+Message-1 was encrypted with the key 'M'. Decrypt it
+
+Message-2 was encrypted with an unknown, 3 letters key. Decrypt it too,
+knowing that it contains the string 'Plekszy-Gladz'
+
+spoiler: xdr

saison-2/sources/espionnage/syldavie/decrypt.py

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+import sys
+import string
+
+
+def rotate(x, y):
+    return (x - y) % 26
+
+
+def shift(letter, n):
+    x = ord(letter) - ord("A")
+    y = rotate(x, n)
+    return chr(ord("A") + y)
+
+
+def rot13(message):
+    message = "".join([x for x in message if x.isalpha()])
+    message = message.upper()
+    res = ""
+    for c in message:
+        res += shift(c, 13)
+    return res
+
+
+def decrypt(key, message):
+    message = "".join([x for x in message if x.isalpha()])
+    message = message.upper()
+    res = ""
+    i = 0
+    for c in message:
+        x = ord(key[i % len(key)]) - ord("A")
+        res += shift(c, x)
+        i += 1
+    return res
+
+
+def try_with_key(key, message):
+    res = decrypt(key, message)
+    if "PLEKSZYGLADZ" in res:
+        return res
+
+
+def main():
+    message = sys.argv[1]
+    print(decrypt('N', message))
+
+    """
+    message = sys.argv[1]
+    letters = string.ascii_uppercase
+    for a in letters:
+        for b in letters:
+            for c in letters:
+                key = a + b + c
+                res = try_with_key(key, message)
+                if res:
+                    print(res)
+                    print("key:", key)
+                    return
+                    """
+
+
+if __name__ == "__main__":
+    main()

saison-2/sources/espionnage/syldavie/message-1.txt

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+GVAGVAFRFGRZCNERQHFCRPGERCERARMYRFZRFHERFARPRFFNVERF

saison-2/sources/espionnage/syldavie/message-2.txt

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+IHDXUVZKRISCBNJWBXIDUWVVODUBPRFQRIRGBUR