def toBase64(raw_bytes):
raw_bytes = bytearray(raw_bytes)
pad_len = 0
while (len(raw_bytes) + pad_len) % 3 != 0:
pad_len = pad_len + 1
raw_bytes.extend([0] * pad_len)
triplets = groupByBlocks(raw_bytes, 3)
new = []
for triplet in triplets:
hex1, hex2, hex3 = triplet
b1 = (hex1 & 0b11111100) >> 2
b2 = (hex1 & 0b00000011)
b3 = (hex2 & 0b11110000) >> 4
b4 = (hex2 & 0b00001111)
b5 = (hex3 & 0b11000000) >> 6
b6 = (hex3 & 0b00111111)
c1 = b1
c2 = (b2 << 4) ^ b3
c3 = (b4 << 2) ^ b5
c4 = b6
d1 = dec2b64[c1]
d2 = dec2b64[c2]
d3 = dec2b64[c3]
d4 = dec2b64[c4]
new.extend([d1, d2, d3, d4])
# padding
if pad_len != 0:
new[-pad_len:] = ["="] * pad_len
return bytearray(new)
def aes_encrypt_ctr(key, msg, nounce):
assert len(key) == 16
assert len(nounce) == 8
# little endian stuff
nounce = bytearray(reversed(nounce))
counter = bytearray("".join(["\x00"] * 8).encode())
output = bytearray()
for block in groupByBlocks(msg, 16):
stream_key = nounce + counter
encrypted_stream_key = aes_encrypt_block(key, stream_key)
output.extend(fixed_xor(encrypted_stream_key, block))
increment_counter(counter)
return bytes(output)
