This will allow implementations other than axTLS.
This commit includes additions of checks and clarifications of exceptions
related to user input.
To make the interface cleaner, I've disallowed switching from encrypt to
decrypt in the same object, as this is not always possible with other
crypto libraries (not all libraries have AES_convert_key like axTLS).
Allow including crypto consts based on compilation settings. Disabled by
default to reduce code size; if one wants extra code readability, can
enable them.
The API follows guidelines of https://www.python.org/dev/peps/pep-0272/,
but is optimized for code size, with the idea that full PEP 0272
compatibility can be added with a simple Python wrapper mode.
The naming of the module follows (u)hashlib pattern.
At the bare minimum, this module is expected to provide:
* AES128, ECB (i.e. "null") mode, encrypt only
Implementation in this commit is based on axTLS routines, and implements
following:
* AES 128 and 256
* ECB and CBC modes
* encrypt and decrypt
