Commit 1e531e31 authored by jan.koester's avatar jan.koester
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deb

parent e0ca5ae8

debian/changelog

+9 −0
Original line number Diff line number Diff line 
libnetplus (20260425+2) unstable; urgency=medium



  * RSA bigInt: switch from fixed 32-bit limbs to portable limb_t/dlimb_t

    typedefs — 64-bit limbs with __uint128_t accumulator on GCC/Clang,

    32-bit fallback on MSVC. Halves limb count for RSA-2048 (64→32),

    yielding ~4x fewer inner-loop iterations in Montgomery CIOS.



 -- Jan Koester <jan.koester@tuxist.de>  Sat, 25 Apr 2026 14:00:00 +0200



libnetplus (20260425+1) unstable; urgency=medium



  * RSA: replace separate multiply + reduce with fused CIOS

src/crypto/rsa.cpp

+169 −150

File changed.

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src/crypto/rsa.h

+20 −9
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@@ -32,23 +32,34 @@ 


#pragma once



// Portable limb types: 64-bit on GCC/Clang, 32-bit fallback on MSVC

#if defined(__SIZEOF_INT128__)

    using limb_t  = uint64_t;

    using dlimb_t = __uint128_t;

    #define LIMB_BITS 64

#else

    using limb_t  = uint32_t;

    using dlimb_t = uint64_t;

    #define LIMB_BITS 32

#endif



namespace netplus {

    class rsa {

    public:

        class bigInt {

            public:

                std::unique_ptr<uint32_t[]> data;

                size_t used; // number of 32-bit words used

                std::unique_ptr<limb_t[]> data;

                size_t used; // number of limb_t words used

                size_t capacity;



                explicit bigInt(size_t cap_words = 64) : used(1), capacity(std::max<size_t>(1, cap_words)) {

                    data = std::make_unique<uint32_t[]>(capacity);

                    std::fill(data.get(), data.get() + capacity, 0);

                    data = std::make_unique<limb_t[]>(capacity);

                    std::fill(data.get(), data.get() + capacity, limb_t(0));

                }



                bigInt(uint32_t val, size_t cap) : used(1), capacity(std::max<size_t>(1, cap)) {

                    data = std::make_unique<uint32_t[]>(capacity);

                    std::fill(data.get(), data.get() + capacity, 0);

                    data = std::make_unique<limb_t[]>(capacity);

                    std::fill(data.get(), data.get() + capacity, limb_t(0));

                    data[0] = val;

                }
@@ -138,12 +149,12 @@ namespace netplus { 
        static bigInt modPow(const bigInt& base, const bigInt& exp, const bigInt& mod);

        static bigInt modInverse(const bigInt& e, const bigInt& phi);

        static bigInt gcd(bigInt a, bigInt b);

        static uint32_t calculateNPrime(uint32_t n0);

        static limb_t calculateNPrime(limb_t n0);

        static bigInt calculateRMod(const bigInt& mod);

        static bigInt calculateR2Mod(const bigInt& mod);

        static bigInt montgomeryMultiply(const bigInt& a, const bigInt& b, const bigInt& mod, uint32_t n_prime);

        static bigInt montgomeryMultiply(const bigInt& a, const bigInt& b, const bigInt& mod, limb_t n_prime);

        static void montgomeryMultiply_into(const bigInt& a, const bigInt& b,

                                             const bigInt& mod, uint32_t n_prime,

                                             const bigInt& mod, limb_t n_prime,

                                             bigInt& scratch, bigInt& out);

        friend class x509cert;

        friend class tls;