Data obfuscation layer for encryption

[asfimport]

Data obfuscation in sensitive columns - for users without access to column encryption keys.

1. Implement on top of basic Parquet encryption 
2. Built-in support for multiple masking mechanisms, with different trade-off between data utility, leakage, and size/throughput overhead
3. Provide interface for plug-in custom masking mechanism
4. Enable storing multiple masked versions of the same column in a file
5. Provide readers with explicit list of column’s masked versions in a file
6. Enable readers to select a masked version of a column
7. Stretch: Implement tools for analysis of file data privacy properties and information leakage
8. Stretch: Leverage privacy analysis tools for tuning file data anonymity
9. Optional: Support aggregated obfuscation

Reporter: Gidon Gershinsky / @ggershinsky
Assignee: Gidon Gershinsky / @ggershinsky

Related issues:

• Parquet modular encryption (depends upon)

PRs and other links:

• discussion googledoc

_{Note: This issue was originally created as PARQUET-1376. Please see the migration documentation for further details.}