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 over GF(2)[X]/(X^8 + X^4 + X^3 + X^2 + 1), 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

GFTest()

Method Summary

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 classic GF(256) exp table for this field polynomial, and the cycle must close back on 1.
void	testSqrAgainstOracle()

Methods inherited from class junit.framework.TestCase

countTestCases, createResult, getName, run, run, runBare, runTest, setName, tearDown, toString

Methods inherited from class junit.framework.Assert

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, fail, fail

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()

testOracleIsTheExpectedField

public void testOracleIsTheExpectedField()

Guard the oracle itself: these are the opening entries of the classic GF(256) exp table for this field polynomial, 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()