shadps4-emu/ext-cryptopp
1
0
Fork 0
mirror of https://github.com/shadps4-emu/ext-cryptopp.git synced 2025-02-17 03:48:38 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fix incorrect InverseMod (GH #602) (#603)

Browse Source
This commit is contained in:
Jeffrey Walton 2018-03-25 00:43:21 -04:00 committed by GitHub
parent b0f7170595
commit ff82b5a886
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 152 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
integer.cpp
View File

@ -4380,7 +4380,20 @@ Integer Integer::InverseMod(const Integer &m) const
CRYPTOPP_ASSERT(m.NotNegative());
if (IsNegative())
return Modulo(m).InverseMod(m);
return Modulo(m).InverseModNext(m);
// Place *this in the range [0, 2m-1]
// http://github.com/weidai11/cryptopp/issues/602
if (*this >= (m << 1))
return Modulo(m).InverseModNext(m);
return InverseModNext(m);
}
Integer Integer::InverseModNext(const Integer &m) const
{
CRYPTOPP_ASSERT(m.NotNegative());
CRYPTOPP_ASSERT(*this < 2*m);
if (m.IsEven())
{
@ -4389,11 +4402,12 @@ Integer Integer::InverseMod(const Integer &m) const
if (*this == One())
return One();
Integer u = m.Modulo(*this).InverseMod(*this);
Integer u = m.Modulo(*this).InverseModNext(*this);
return !u ? Zero() : (m*(*this-u)+1)/(*this);
}
SecBlock<word> T(m.reg.size() * 4);
// AlmostInverse requires a 4x workspace
IntegerSecBlock T(m.reg.size() * 4);
Integer r((word)0, m.reg.size());
unsigned k = AlmostInverse(r.reg, T, reg, reg.size(), m.reg, m.reg.size());
DivideByPower2Mod(r.reg, r.reg, k, m.reg, m.reg.size());

5
integer.h
View File

@ -630,6 +630,11 @@ public:
CRYPTOPP_DLL friend Integer CRYPTOPP_API a_exp_b_mod_c(const Integer &x, const Integer& e, const Integer& m);
#endif
protected:
// https://github.com/weidai11/cryptopp/issues/602
Integer InverseModNext(const Integer &n) const;
private:
Integer(word value, size_t length);

8
test.cpp
View File

@ -956,12 +956,14 @@ bool Validate(int alg, bool thorough, const char *seedInput)
case 9998: result = TestPolynomialMod2(); break;
// http://github.com/weidai11/cryptopp/issues/336
case 9997: result = TestIntegerBitops(); break;
// http://github.com/weidai11/cryptopp/issues/602
case 9996: result = TestIntegerOps(); break;
// http://github.com/weidai11/cryptopp/issues/360
case 9996: result = TestRounding(); break;
case 9995: result = TestRounding(); break;
// http://github.com/weidai11/cryptopp/issues/242
case 9995: result = TestHuffmanCodes(); break;
case 9994: result = TestHuffmanCodes(); break;
// http://github.com/weidai11/cryptopp/issues/346
case 9994: result = TestASN1Parse(); break;
case 9993: result = TestASN1Parse(); break;
#endif
default: return false;

122
validat0.cpp
View File

@ -3193,6 +3193,128 @@ bool TestIntegerBitops()
return opa && opo && opx;
}
bool TestIntegerOps()
{
std::cout << "\nTesting Integer operations...\n\n";
bool pass=true, result;
// http://github.com/weidai11/cryptopp/issues/602
Integer a("0x2F0500010000018000000000001C1C000000000000000A000B0000000000000000000000000000FDFFFFFF00000000");
Integer b("0x3D2F050001");
result = (0x3529E4FEBC == a.InverseMod(b));
pass = result && pass;
if (!result)
std::cout << "FAILED: InverseMod operation\n";
RandomNumberGenerator& prng = GlobalRNG();
for (unsigned int i=0; i<128; ++i)
{
Integer a(prng, 1024), m(prng, 1024);
a++, m++; // make non-0
// Corner cases
switch (i)
{
case 0:
a = 0;
break;
case 1:
a = m-1;
break;
case 2:
a = m;
break;
case 3:
a = m+1;
break;
case 4:
a = 2*m-1;
break;
case 5:
a = 2*m;
break;
case 6:
a = 2*m+1;
break;
case 7:
a = (m<<256)-1;
break;
case 8:
a = (m<<256);
break;
case 9:
a = (m<<256)+1;
default:
;;
}
Integer x = a.InverseMod(m);
Integer y = (a % m).InverseMod(m);
Integer z = (a * y).Modulo(m);
if (GCD(a,m) == 1) // coprime?
result = (x == y) && (z == 1) && (a_times_b_mod_c(a, x, m) == 1);
else
result = (x == y);
pass = result && pass;
if (!result)
std::cout << "FAILED: InverseMod operation\n";
}
for (unsigned int i=0; i<128; ++i)
{
Integer m(prng, 32);
m++; // make non-0
for (unsigned int j=0; j<256; j+=4)
{
Integer a((m << j)-1);
Integer x = a.InverseMod(m);
Integer y = (a % m).InverseMod(m);
Integer z = (a * y).Modulo(m);
if (GCD(a,m) == 1) // coprime?
result = (x == y) && (z == 1) && (a_times_b_mod_c(a, x, m) == 1);
else
result = (x == y);
pass = result && pass;
if (!result)
std::cout << "FAILED: InverseMod operation\n";
}
}
for (unsigned int i=0; i<128; ++i)
{
Integer a(prng, 4096), m(prng, 32);
a++, m++; // make non-0
Integer x = a.InverseMod(m);
Integer y = (a % m).InverseMod(m);
Integer z = (a * y).Modulo(m);
if (GCD(a,m) == 1) // coprime?
result = (x == y) && (z == 1) && (a_times_b_mod_c(a, x, m) == 1);
else
result = (x == y);
pass = result && pass;
if (!result)
std::cout << "FAILED: InverseMod operation\n";
}
if (pass)
std::cout << "passed:";
else
std::cout << "FAILED:";
std::cout << " Integer::InverseMod operations\n";
return pass;
}
#endif
NAMESPACE_END // Test

4
validate.h
View File

@ -128,6 +128,8 @@ bool TestSecBlock();
bool TestPolynomialMod2();
// http://github.com/weidai11/cryptopp/issues/336
bool TestIntegerBitops();
// http://github.com/weidai11/cryptopp/issues/602
bool TestIntegerOps();
// http://github.com/weidai11/cryptopp/issues/360
bool TestRounding();
// http://github.com/weidai11/cryptopp/issues/242
@ -189,7 +191,7 @@ private:
};
#endif
// Safer functions on Windows for C&A, https://github.com/weidai11/cryptopp/issues/55
// Safer functions on Windows for C&A, http://github.com/weidai11/cryptopp/issues/55
inline std::string TimeToString(const time_t& t)
{
#if (CRYPTOPP_MSC_VERSION >= 1400)