def decode(self, chiper: bytes):
result = []
chiper = [x for x in chiper if is_int_alpha(x)]
chiper_len = len(chiper)
a_idx = 0
while a_idx < chiper_len:
if is_int_alpha(chiper[a_idx]):
a_idx, b_idx, a, b = self.get_letter_pair(
a_idx, chiper, chiper_len)
a_new, b_new = self.process_pair(a, b, decode=True)
result.append(a_new + ord("a"))
result.append(b_new + ord("a"))
else:
result.append(chiper[a_idx])
a_idx += 1
return bytes(result)
def encode(self, plain: bytes):
result = []
plain = [x for x in plain if is_int_alpha(x)]
plain_len = len(plain)
a_idx = 0
while a_idx < plain_len:
if is_int_alpha(plain[a_idx]):
a_idx, b_idx, a, b = self.get_letter_pair(
a_idx, plain, plain_len)
a_new, b_new = self.process_pair(a, b)
result.append(a_new + ord("a"))
result.append(b_new + ord("a"))
else:
result.append(plain[a_idx])
a_idx += 1
return bytes(result)
def prepare_input(self, input: bytes):
input = input.strip().lower()
result = [x for x in input if is_int_alpha(x)]
if len(result) % self.k != 0:
# pad message
padlen = self.k - (len(result) % self.k)
# print(f"{len(result)=} {len(result) % self.k=} {padlen=}")
for x in range(padlen):
c = (x % 26) + ord("a")
result.append(c)
return bytes(result)
def encode(self, plain: bytes) -> bytes:
result = []
key_idx = 0
key_len = len(self.key)
for c in plain:
if is_int_alpha(c):
c_ord = lalpha_ord(c)
k_ord = lalpha_ord(self.key[key_idx])
res_ord = (c_ord + k_ord) % 26 + ord("a")
result.append(res_ord)
key_idx = (key_idx + 1) % key_len
else:
result.append(c)
return bytes(result)
def decode(self, chiper: bytes) -> bytes:
result = []
key_idx = 0
key_len = len(self.key)
for c in chiper:
if is_int_alpha(c):
c_ord = lalpha_ord(c)
k_ord = lalpha_ord(self.key[key_idx])
res_ord = (c_ord - k_ord + 26) % 26 + ord("a")
result.append(res_ord)
key_idx = (key_idx + 1) % key_len
else:
result.append(c)
return bytes(result)
def decode(self, chiper: bytes) -> bytes:
result = []
key_idx = 0
key_len = len(self.key)
for c in chiper:
if is_int_alpha(c):
c_ord = lalpha_ord(c)
if key_idx >= key_len:
k_ord = result[key_idx - key_len]
else:
k_ord = lalpha_ord(self.key[key_idx])
res_ord = (c_ord - k_ord) % 26 + ord("a")
result.append(res_ord)
key_idx = key_idx + 1
else:
result.append(c)
return bytes(result)
def decode(self, chiper: bytes) -> bytes:
result = []
key_idx = 0
key_len = len(self.key)
for c in chiper:
if is_int_alpha(c):
c_ord = lalpha_ord(c)
k_ord = lalpha_ord(self.key[key_idx])
for row_num in range(len(self.square)):
row = self.square[row_num]
res_ord = row[k_ord] - ord("a")
if res_ord == c_ord:
break
result.append(row_num + ord("a"))
key_idx = (key_idx + 1) % key_len
else:
result.append(c)
return bytes(result)
def get_letter_pair(self, a_idx, text, text_len):
a = text[a_idx]
b_idx = a_idx + 1
while True:
if b_idx >= text_len:
b = ord("x")
break
b = text[b_idx]
if is_int_alpha(b):
if a == b:
b_idx = a_idx
b = ord("x")
break
else:
b_idx += 1
continue
a_idx = b_idx + 1
return a_idx, b_idx, lalpha_ord(a), lalpha_ord(b)
