143 lines
3.7 KiB
C++
143 lines
3.7 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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By using JUCE, you agree to the terms of both the JUCE 5 End-User License
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Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
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27th April 2017).
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End User License Agreement: www.juce.com/juce-5-licence
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Privacy Policy: www.juce.com/juce-5-privacy-policy
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Or: You may also use this code under the terms of the GPL v3 (see
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www.gnu.org/licenses).
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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RSAKey::RSAKey()
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{
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}
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RSAKey::RSAKey (const String& s)
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{
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if (s.containsChar (','))
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{
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part1.parseString (s.upToFirstOccurrenceOf (",", false, false), 16);
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part2.parseString (s.fromFirstOccurrenceOf (",", false, false), 16);
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}
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else
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{
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// the string needs to be two hex numbers, comma-separated..
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jassertfalse;
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}
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}
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RSAKey::~RSAKey()
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{
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}
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bool RSAKey::operator== (const RSAKey& other) const noexcept
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{
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return part1 == other.part1 && part2 == other.part2;
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}
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bool RSAKey::operator!= (const RSAKey& other) const noexcept
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{
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return ! operator== (other);
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}
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bool RSAKey::isValid() const noexcept
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{
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return operator!= (RSAKey());
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}
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String RSAKey::toString() const
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{
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return part1.toString (16) + "," + part2.toString (16);
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}
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bool RSAKey::applyToValue (BigInteger& value) const
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{
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if (part1.isZero() || part2.isZero() || value <= 0)
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{
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jassertfalse; // using an uninitialised key
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value.clear();
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return false;
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}
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BigInteger result;
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while (! value.isZero())
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{
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result *= part2;
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BigInteger remainder;
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value.divideBy (part2, remainder);
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remainder.exponentModulo (part1, part2);
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result += remainder;
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}
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value.swapWith (result);
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return true;
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}
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BigInteger RSAKey::findBestCommonDivisor (const BigInteger& p, const BigInteger& q)
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{
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// try 3, 5, 9, 17, etc first because these only contain 2 bits and so
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// are fast to divide + multiply
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for (int i = 2; i <= 65536; i *= 2)
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{
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const BigInteger e (1 + i);
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if (e.findGreatestCommonDivisor (p).isOne() && e.findGreatestCommonDivisor (q).isOne())
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return e;
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}
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BigInteger e (4);
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while (! (e.findGreatestCommonDivisor (p).isOne() && e.findGreatestCommonDivisor (q).isOne()))
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++e;
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return e;
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}
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void RSAKey::createKeyPair (RSAKey& publicKey, RSAKey& privateKey,
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const int numBits, const int* randomSeeds, const int numRandomSeeds)
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{
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jassert (numBits > 16); // not much point using less than this..
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jassert (numRandomSeeds == 0 || numRandomSeeds >= 2); // you need to provide plenty of seeds here!
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BigInteger p (Primes::createProbablePrime (numBits / 2, 30, randomSeeds, numRandomSeeds / 2));
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BigInteger q (Primes::createProbablePrime (numBits - numBits / 2, 30, randomSeeds == nullptr ? 0 : (randomSeeds + numRandomSeeds / 2), numRandomSeeds - numRandomSeeds / 2));
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const BigInteger n (p * q);
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const BigInteger m (--p * --q);
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const BigInteger e (findBestCommonDivisor (p, q));
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BigInteger d (e);
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d.inverseModulo (m);
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publicKey.part1 = e;
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publicKey.part2 = n;
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privateKey.part1 = d;
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privateKey.part2 = n;
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}
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} // namespace juce
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