Problems with equality operation

[amiller]

There are several problems with the euqality implementation.

• 1. The intended functionality is that equal([x], [y]) should return [1] if x==y, and [0] otherwise. However, the implementation appears to be incorrect, and it returns [0] if x!=y. If x==y, it returns an arbitrary nonzero number, not necessarily [1].
• 2. There is no documentation for the equality function indicating what the intended behavior should be.
• 3. The test case is not precise enough to serve as documentation either. The test case opens the returned value, but does not check that it is either [0] or [1], instead only checks the python "truth" value, hence the test passes even if the return value is any non-zero value.
  https://github.com/initc3/HoneyBadgerMPC/blob/dev/tests/progs/mixins/test_share_comparison.py#L65
• 4. The source code is missing references, both to the paper, and to the implementation in Viff that this was built from.