required key length is wrong

[saks]

from rfc

5.2.2.1. AES_CBC_HMAC_SHA2 Encryption
The number of octets in the input key K MUST be the sum of
MAC_KEY_LEN and ENC_KEY_LEN. The values of these parameters are
specified by the Authenticated Encryption algorithms in Sections
5.2.3 through 5.2.5.
5.2.3. AES_128_CBC_HMAC_SHA_256
The input key K is 32 octets long.
ENC_KEY_LEN is 16 octets.
MAC_KEY_LEN is 16 octets.
5.2.5. AES_256_CBC_HMAC_SHA_512 AES_256_CBC_HMAC_SHA_512 is based on AES_128_CBC_HMAC_SHA_256, but
with the following differences: The input key K is 64 octets long instead of 32.
ENC_KEY_LEN is 32 octets instead of 16.
MAC_KEY_LEN is 32 octets instead of 16.

but in code:

local function derive_keys(enc, secret_key)
  local key_size_bytes = 16
  if enc == str_const.A128CBC_HS256 then
    key_size_bytes = 16
  elseif enc == str_const.A256CBC_HS512 then
    key_size_bytes = 32
  end
  if not secret_key then
    secret_key =  resty_random.bytes(key_size_bytes,true)
  end
  if #secret_key ~= key_size_bytes then
    error({reason="The pre-shared content key must be ".. key_size_bytes})
  end
  local derived_key_size = key_size_bytes / 2
  mac_key = string_sub(secret_key, 1, derived_key_size)
  enc_key =string_sub(secret_key, derived_key_size)
  return secret_key, mac_key, enc_key
end

[SkyLothar]

fixed in 050627

Thanks!

[saks]

Great! BTW, I think it would be nice to make this library compatible with other implementations (with RFC). Right now I'm working on PR. Would be great to hear your opinion.
Thanks!

[saks]

Fixed by #45