def decode(ciphertext, key):
square = mix_alphabet(key, ALPHABET25)
digraphs = split_string_blocks(ciphertext, 2)
plaintext = str()
for digraph in digraphs:
#get both chars, their coordinates
char1, char2 = list(digraph)
row1, column1 = get_coordinates(square, char1)
row2, column2 = get_coordinates(square, char2)
encoded_row1, encoded_column1 = row1, column1
encoded_row2, encoded_column2 = row2, column2
#apply transformation rules
if row1 != row2 and column1 != column2: # making a rectangle - take the other 2 corners, with the same row respectively
encoded_row1, encoded_column1 = row1, column2
encoded_row2, encoded_column2 = row2, column1
elif row1 != row2 and column1 == column2: # same column - get the caracter up
encoded_row1 = (row1 - 1) % 5
encoded_row2 = (row2 - 1) % 5
elif row1 == row2 and column1 != column2: # same row - get the caracter left
encoded_column1 = (column1 - 1) % 5
encoded_column2 = (column2 - 1) % 5
#output resulting chars
encoded_char1 = get_char(square, encoded_row1, encoded_column1)
encoded_char2 = get_char(square, encoded_row2, encoded_column2)
plaintext += encoded_char1 + encoded_char2
return plaintext
def decode(ciphertext, key):
square = mix_alphabet(key, ALPHABET25)
digraphs = split_string_blocks(ciphertext, 2)
plaintext = str()
for digraph in digraphs:
#get both chars, their coordinates
char1, char2 = list(digraph)
row1, column1 = get_coordinates(square, char1)
row2, column2 = get_coordinates(square, char2)
encoded_row1, encoded_column1 = row1, column1
encoded_row2, encoded_column2 = row2, column2
#apply transformation rules
if row1 != row2 and column1 != column2: # making a rectangle - take the other 2 corners, with the same row respectively
encoded_row1, encoded_column1 = row1, column2
encoded_row2, encoded_column2 = row2, column1
elif row1 != row2 and column1 == column2: # same column - get the caracter up
encoded_row1 = (row1 - 1) % 5
encoded_row2 = (row2 - 1) % 5
elif row1 == row2 and column1 != column2: # same row - get the caracter left
encoded_column1 = (column1 - 1) % 5
encoded_column2 = (column2 - 1) % 5
#output resulting chars
encoded_char1 = get_char(square, encoded_row1, encoded_column1)
encoded_char2 = get_char(square, encoded_row2, encoded_column2)
plaintext += encoded_char1 + encoded_char2
return plaintext
def second_sifra(data, key, alphabet_key):
#now the substitution alphabet is generated from a passphrase
consonants = mix_alphabet(alphabet_key, "bcdfghlmnpqrstxyz")
#then we'll work on the vowels, but we'll insert them every 3 character
#let's split the consonants string
consonants_blocks = split_string_blocks(consonants, 3)
#and parse the key for its used vowels
vowels = mix_alphabet(alphabet_key, "aeiou")
#let's merge the consonants and vowels data
alphabet = "".join(i + j
for i, j in zip_extend(consonants_blocks, list(vowels)))
#assert alphabet == "rmqacntupsbidfgehlxoyz"
constant_part, rotated_part = alphabet[:11], Str(alphabet[11:])
#now to generate the pairs, we'll do the same, but merge the vowel every char blocks
consonants_blocks = split_string_blocks(consonants, 1)
pairsString = Str("".join(
i + j for i, j in zip_extend(consonants_blocks, list(vowels))))
pairs = pairsString.splitblock(2)
#now we have the pairs, the initial substitution alphabet
#let's generate the 'rotated' alphabet for each pair
alphabets = dict()
for index, pair in enumerate(pairs):
#let's get the pair by its first char in the order
alphabets[pair] = constant_part + (rotated_part >> index)
# now the actual encryption
# for this cipher, the xth character of the key is used to decrypt the xth word (space separated) of the plaintext
output = str()
key_index = 0
for char in data:
pair = [p for p in alphabets if key[key_index] in p]
if pair:
char = substitute(char, alphabets[pair[0]])
if char == ' ':
key_index += 1
output += char
return output
def second_sifra(data, key, alphabet_key):
#now the substitution alphabet is generated from a passphrase
consonants = mix_alphabet(alphabet_key, "bcdfghlmnpqrstxyz")
#then we'll work on the vowels, but we'll insert them every 3 character
#let's split the consonants string
consonants_blocks = split_string_blocks(consonants, 3)
#and parse the key for its used vowels
vowels = mix_alphabet(alphabet_key, "aeiou")
#let's merge the consonants and vowels data
alphabet = "".join(i + j for i, j in zip_extend(consonants_blocks, list(vowels)))
#assert alphabet == "rmqacntupsbidfgehlxoyz"
constant_part, rotated_part = alphabet[:11], Str(alphabet[11:])
#now to generate the pairs, we'll do the same, but merge the vowel every char blocks
consonants_blocks = split_string_blocks(consonants, 1)
pairsString = Str("".join(i + j for i, j in zip_extend(consonants_blocks, list(vowels))))
pairs = pairsString.splitblock(2)
#now we have the pairs, the initial substitution alphabet
#let's generate the 'rotated' alphabet for each pair
alphabets = dict()
for index, pair in enumerate(pairs):
#let's get the pair by its first char in the order
alphabets[pair] = constant_part + (rotated_part >> index)
# now the actual encryption
# for this cipher, the xth character of the key is used to decrypt the xth word (space separated) of the plaintext
output = str()
key_index = 0
for char in data:
pair = [p for p in alphabets if key[key_index] in p]
if pair:
char = substitute(char, alphabets[pair[0]])
if char == ' ':
key_index += 1
output += char
return output