org.bouncycastle.pqc.crypto.hqc

Class GFTest

java.lang.Object

junit.framework.Assert

junit.framework.TestCase

org.bouncycastle.pqc.crypto.hqc.GFTest

All Implemented Interfaces:

junit.framework.Test

public class GFTest
extends junit.framework.TestCase

Regression tests for HQC's GF(2^8) arithmetic.

GF used to be implemented with log/exp/inv/sqr lookup tables indexed by field elements, which leaked secret-derived values through the cache; it is now table-free and branch-free. These tests pin the arithmetic to the values the tables produced, so a future change cannot alter a result while the HQC known-answer tests happen to keep passing on the subset of inputs they exercise.

The expected values come from an independent construction: log and exp tables built here by iterating the generator X + 1 over GF(2)[X]/(X^8 + X^4 + X^3 + X + 1), the field of the HQC specification of 2026-10-12 (X alone is not primitive in this field, its order is 51), so the oracle takes a different computational route (discrete logs) from the implementation (carryless multiply and reduce). Field laws are checked as well, in case both sides were to be wrong the same way.

Constructor Summary

Constructors

Constructor and Description
GFTest()

Method Summary

Modifier and Type	Method and Description
void	setUp()
void	testDivAgainstOracle()
void	testFieldLaws()
void	testInvAgainstOracle()
void	testMul3AgainstOracle() mul3 is exercised on a stride rather than all 16777216 triples, to keep the legacy Ant builds (which run this on a real JRE 1.3/1.4) quick; mul itself is covered exhaustively above and mul3 is defined in terms of it.
void	testMulAgainstOracle()
void	testOracleIsTheExpectedField() Guard the oracle itself: these are the opening entries of the exp table for this field polynomial and generator (the reference implementation's gf_exp), and the cycle must close back on 1.
void	testSqrAgainstOracle()

Methods inherited from class junit.framework.TestCase

assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertEquals, assertFalse, assertFalse, assertNotNull, assertNotNull, assertNotSame, assertNotSame, assertNull, assertNull, assertSame, assertSame, assertTrue, assertTrue, countTestCases, createResult, fail, fail, failNotEquals, failNotSame, failSame, format, getName, run, run, runBare, runTest, setName, tearDown, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

GFTest

public GFTest()

Method Detail

setUp

public void setUp()

Overrides:

setUp in class junit.framework.TestCase

testOracleIsTheExpectedField

public void testOracleIsTheExpectedField()

Guard the oracle itself: these are the opening entries of the exp table for this field polynomial and generator (the reference implementation's gf_exp), and the cycle must close back on 1.

testMulAgainstOracle

public void testMulAgainstOracle()

testSqrAgainstOracle

public void testSqrAgainstOracle()

testInvAgainstOracle

public void testInvAgainstOracle()

testDivAgainstOracle

public void testDivAgainstOracle()

testMul3AgainstOracle

public void testMul3AgainstOracle()

mul3 is exercised on a stride rather than all 16777216 triples, to keep the legacy Ant builds (which run this on a real JRE 1.3/1.4) quick; mul itself is covered exhaustively above and mul3 is defined in terms of it.

testFieldLaws

public void testFieldLaws()