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An implementation of columnar transposition cipher
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from math import ceil | |
def columnarEncrypt(message, key): | |
print('your message is ', message) | |
message = message.replace(' ', '') | |
matrix_size = len(key) | |
rows = len(message)/len(key) | |
message = message.ljust(ceil(rows)*len(key), 'X') | |
print('message after padding', message) | |
message = list(message) | |
box = [] | |
i = 0 | |
for row in range(ceil(rows)): | |
box.append(message[i:i+len(key)]) | |
i += len(key) | |
print(box) | |
priority_list = [ord(val) for val in list(key)] | |
box_encrypted = [] | |
for r in box: | |
row_tuples = [] | |
for c in range(len(r)): | |
row_tuples.append((r[c], priority_list[c])) | |
row_tuples.sort(key=lambda x: x[1]) | |
encrypted_row = [v[0] for v in row_tuples] | |
box_encrypted.append(encrypted_row) | |
print(box_encrypted) | |
encrypted_text = [] | |
for line in box_encrypted: | |
encrypted_text.extend(line) | |
print("Your cipher text is ", ''.join(encrypted_text)) | |
def columnarDecrypt(ciphertext, key): | |
print('your Cipher Text is ', ciphertext) | |
# message = list(message.replace(' ', '')) | |
ciphertext = ciphertext.replace(' ', '') | |
matrix_size = len(key) | |
rows = len(ciphertext)/len(key) | |
ciphertext = list(ciphertext) | |
box = [] | |
i = 0 | |
for row in range(ceil(rows)): | |
box.append(ciphertext[i:i+len(key)]) | |
i += len(key) | |
print(box) | |
key_list = list(key) | |
sortedkey_list = key_list | |
sortedkey_list = sorted(key_list) | |
sortedMessage = [] | |
for r in box: | |
for k in key_list: | |
sortedMessage.append(r[sortedkey_list.index(k)]) | |
print('Your Decrypted Message is ', ''.join(sortedMessage)) | |
columnarEncrypt('defend the east wall of the castle', 'READY') | |
columnarDecrypt('feednhetdetwsaaoflltcaehseXltX', 'READY') |
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