The crypto module provides various functions for working with cryptographic algorithms.
This is work in progress, for now only a number of hashing functions are available:
* SHA1
* SHA256
* SHA224
* SHA512
* SHA384
* MD5
All except MD5 are enabled by default. To disable algorithms you don't need, find the "Crypto module hashing algorithms" under the NodeMCU modules section in menuconfig.
## crypto.new_hash()
Create a digest/hash object that can have any number of strings added to it. Object has `update` and `finalize` functions.
#### Syntax
`hashobj = crypto.new_hash(algo)`
#### Parameters
`algo` the hash algorithm to use, case insensitive string
#### Returns
Hasher object with `update` and `finalize` functions available.