Rust and Sage Implementation do not hash to the same point on the same input

[drskalman]

See: w3f-grants-archive/Indifferentiable-hashing-to-ordinary-elliptic-curves-of-j-0-with-the-cost-of-one-exponentiation@6aefa9c

n$ sage Indifferentiable\ hashing\ with\ the\ cost\ of\ one\ exponentiation.sage
FF
======================================================================
FAIL: test_bls12_377_test_vector (__main__.TestIndiffJInvJ0Hash)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/skalman/code/Indifferentiable-hashing-to-ordinary-elliptic-curves-of-j-0-with-the-cost-of-one-exponentiation/Indifferentiable hashing with the cost of one exponentiation.sage.py", line 434, in test_bls12_377_test_vector
    assert(X/Z == bls12_377_test_vector[i*_sage_const_2 ] and Y/Z == bls12_377_test_vector[i*_sage_const_2 +_sage_const_1 ])
AssertionError

======================================================================
FAIL: test_bls12_381_test_vector (__main__.TestIndiffJInvJ0Hash)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/skalman/code/Indifferentiable-hashing-to-ordinary-elliptic-curves-of-j-0-with-the-cost-of-one-exponentiation/Indifferentiable hashing with the cost of one exponentiation.sage.py", line 420, in test_bls12_381_test_vector
    assert(X/Z == bls12_381_test_vector[i*_sage_const_2 ] and Y/Z == bls12_381_test_vector[i*_sage_const_2 +_sage_const_1 ])
AssertionError

----------------------------------------------------------------------
Ran 2 tests in 13.365s

FAILED (failures=2)

[zhenfeizhang]

Somewhere within those commitments Dimitri-Koshelev/Indifferentiable-hashing-to-ordinary-elliptic-curves-of-j-0-with-the-cost-of-one-exponentiation@main...w3f-grants-archive:Indifferentiable-hashing-to-ordinary-elliptic-curves-of-j-0-with-the-cost-of-one-exponentiation:main

the y coordinates sign got flipped. It should be fixed with 2ebfb6f now

please use the new test vectors and try again @drskalman

[drskalman]

I used the updated test vetors. The test passes for BLS12-377 but they still fails for BLS12-381:

======================================================================
FAIL: test_bls12_381_test_vector (__main__.TestIndiffJInvJ0Hash)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/skalman/code/Indifferentiable-hashing-to-ordinary-elliptic-curves-of-j-0-with-the-cost-of-one-exponentiation/Indifferentiable hashing with the cost of one exponentiation.sage.py", line 421, in test_bls12_381_test_vector
    assert(X/Z == bls12_381_test_vector[i*_sage_const_2 ] and Y/Z == bls12_381_test_vector[i*_sage_const_2 +_sage_const_1 ])
AssertionError

----------------------------------------------------------------------
Ran 6 tests in 13.791s

FAILED (failures=1)

[zhenfeizhang]

It should be fixed now.

[drskalman]

Indeed:

----------------------------------------------------------------------
Ran 6 tests in 14.782s

OK