Merge pull request #169 from RishabhBhatnagar/master

Add RailFence Cipher in Cryptography

Author: ionicc

Cryptography/src/RailFenceCipher/generic_rail_fence.py

@@ -0,0 +1,25 @@
+def fence(lst, height):
+    _fence = [[None] * len(lst) for n in range(height)]
+    rails = [*range(0, height - 1), *range(height - 1, 0, -1)]  # sawtooth.
+    for n, x in enumerate(lst): 
+        _fence[rails[n % len(rails)]][n] = x
+    return [c for c in sum(_fence, []) if c is not None]
+
+
+def encode(text, h):
+    return ''.join(fence(text, h))
+
+
+def decode(cipher, h):
+    pos = fence(range(len(cipher)), h)
+    return ''.join(cipher[pos.index(i)] for i in range(len(cipher)))
+
+
+if __name__ == '__main__':
+    height = 3
+    plain_text = "Hacktoberfest"
+    cipher_text = encode(plain_text, height)
+    decoded = decode(cipher_text, height)
+
+    assert decoded == plain_text
+

Cryptography/src/RailFenceCipher/rf.py

@@ -0,0 +1 @@
+https://github.com/codezoned/ScriptsDump