def encode(filename, keys):
fi = open(filename, 'rb')
plaintext = fi.read()
fi.close()
header_bits, text_bits = split_header_and_content(plaintext)
text_bits = add_pads_if_necessary(text_bits)
final_cipher = ''
for i in range(0, 64):
text_bits[i] ^= iv[i]
len_text_bits = len(text_bits)
for i in range(0, len_text_bits, 64):
final_cipher += DES(text_bits, i, (i + 64), keys)
if i < len_text_bits - 64:
for j in range(i + 64, i + 128):
text_bits[j] ^= int(final_cipher[j - 64])
# conversion of binary cipher into hex-decimal form
fo = open("encrypted_cbc.bmp", "wb")
header_str = ""
for each in header_bits:
header_str += str(each)
final_cipher = header_str + final_cipher
i = 0
print("The length of final_cipher")
print(len(final_cipher))
while i < len(final_cipher) - 8:
val = bin_to_dec(final_cipher[i:i + 4]) * 16 + bin_to_dec(
final_cipher[i + 4:i + 8])
fo.write(struct.pack('B', val))
i += 8
fo.close()
print('the cipher is saved in encrypted_ecb.bmp')
def encode(filename, keys):
fi = open(filename, 'rb', )
plaintext = fi.read()
fi.close()
header_bits, text_bits = split_header_and_content(plaintext)
text_bits = add_pads_if_necessary(text_bits)
final_cipher = ''
for i in range(0, len(text_bits), 64):
final_cipher += DES(text_bits, i, (i + 64), keys)
# conversion of binary cipher into hex-decimal form
fo = open("encrypted_ecb.bmp", "wb")
header_str = ""
for each in header_bits:
header_str += str(each)
final_cipher = header_str + final_cipher
i = 0
print("The length of final_cipher")
print(len(final_cipher))
while i < len(final_cipher) - 8:
val = bin_to_dec(final_cipher[i:i + 4]) * 16 + bin_to_dec(final_cipher[i + 4:i + 8])
fo.write(struct.pack('B', val))
i += 8
fo.close()
print('the cipher is saved in encrypted_ecb.bmp')
def decode(filename, keys):
fi = open(filename, "rb")
cipher = fi.read()
fi.close()
cipher_bits = []
header_str = ''
for i in cipher:
cipher_bits.extend(to_binary(ord(i)))
header_bits = cipher_bits[0:HEADER_LENGTH]
text_bits = cipher_bits[HEADER_LENGTH:]
for i in header_bits:
header_str += str(i)
text_bits = add_pads_if_necessary(text_bits)
keys.reverse()
bin_mess = ''
for i in range(0, len(text_bits), 64):
bin_mess += DES(text_bits, i, (i + 64), keys)
text_mess = header_str + bin_mess
i = 0
fo = open("decrypted_ecb.bmp", 'wb')
print("The length of final_cipher")
print(len(text_mess))
while i < len(text_mess) - 8:
val = bin_to_dec(text_mess[i:i + 4]) * 16 + bin_to_dec(text_mess[i + 4:i + 8])
fo.write(struct.pack('B', val))
i += 8
fo.close()
print('the original image has been saved in decrypted_ecb.bmp')
def decode(filename, keys):
fi = open(filename, "rb")
cipher = fi.read()
fi.close()
cipher_bits = []
header_str = ''
for i in cipher:
cipher_bits.extend(to_binary(ord(i)))
header_bits = cipher_bits[0:HEADER_LENGTH]
text_bits = cipher_bits[HEADER_LENGTH:]
for i in header_bits:
header_str += str(i)
text_bits = add_pads_if_necessary(text_bits)
keys.reverse()
bin_mess = ''
for i in range(0, len(text_bits), 64):
bin_mess += DES(text_bits, i, (i + 64), keys)
text_mess = header_str + bin_mess
i = 0
fo = open("decrypted_ecb.bmp", 'wb')
print("The length of final_cipher")
print(len(text_mess))
while i < len(text_mess) - 8:
val = bin_to_dec(text_mess[i:i + 4]) * 16 + bin_to_dec(
text_mess[i + 4:i + 8])
fo.write(struct.pack('B', val))
i += 8
fo.close()
print('the original image has been saved in decrypted_ecb.bmp')