refactor(crypto): export type definitions

[paroxysm]

Proposed changes

Resolves #1792

This PR simply exposes the types in crypto, but it doesn't propagate those types around their dependencies. The code-base is already using these types already.
The next step would be to improve type-safety, replacing a lot of 'any' with their actual expected types. This will require a lot more effort because it'll start introducing compile errors all over :)

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (improve a current implementation without adding a new feature or fixing a bug)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Build (changes that affect the build system)
• Docs (documentation only changes)
• Test (adding missing tests or fixing existing tests)
• Other... Please describe:

• I have read the CONTRIBUTING documentation
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[faustbrian]

@paroxysm you need to restart your CircleCI build because it failed