meta_hash update

[bauman]

this module was poorly written. Must have been an off day for the author.

See #4

Still needs hmac

[csmutz]

Bauman,

The idea of making the hashes configurable is sound. We will not accept the pull request as is, as there are a few issues we’d like addressed:

1. Remove the truncated SHA512 and don’t worry about adding HMACs. Those items could be useful for an internal identifier, but probably don’t belong in meta_hash
2. Set defaults to same as original (md5, sha1, sha256, sha512). (Keeping ssdeep out of default is OK and making ssdeep optional is good)
3. Consider renaming the sane_defaults variable—not all will agree on sanity of the defaults
4. Consider adding configuration items consistent with the module arguments

Lastly, if you’d like your name or organization in the copyright notice, please add that or we’ll assume you’d like to remain out of copyright notice for this file.

[csmutz]

This allows a large degree of flexibility by the user. To remain backwards compatible, could you make sha1 on by default as well? Would you turn ssdeep on by default also, put a try/catch around ssdeep so that ssdeep remains optional (no errors due to lack of ssdeep).

[csmutz]

We appreciate the improvements you have provided and are willing to accept this pull request when the default matches what occurred before (ssdeep hashing occurs, if ssdeep module is available).