CWE-ou-minkata/Sources/Plasma/NucleusLib/pnEncryption/plBigNum.h

/*==LICENSE==*

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*==LICENSE==*/

#ifndef plBigNum_inc
#define plBigNum_inc

/*****************************************************************************
*
*   plBigNum class
*
***/

#include "HeadSpin.h"
#include <openssl/bn.h>

class plBigNum
{
private:
    BIGNUM m_number;
    mutable BN_CTX* m_context;

    BN_CTX* GetContext() const
    {
        if (!m_context)
            m_context = BN_CTX_new();
        return m_context;
    }

public:
    plBigNum();
    plBigNum(const plBigNum& a);
    plBigNum(uint32_t a);
    plBigNum(uint32_t bytess, const void* data, bool le=false);
    ~plBigNum();

    plBigNum& operator=(const plBigNum& a)
    {
        BN_copy(&m_number, &a.m_number);
        return *this;
    }

    // Constant parameters need not be distinct from the destination or from
    // each other

    void Add(const plBigNum& a, uint32_t b)
    {
        // this = a + b
        BN_copy(&m_number, &a.m_number);
        BN_add_word(&m_number, b);
    }

    void Add(const plBigNum& a, const plBigNum& b)
    {
        // this = a + b
        BN_add(&m_number, &a.m_number, &b.m_number);
    }

    int Compare(uint32_t a) const;

    int Compare(const plBigNum& a) const
    {
        return BN_cmp(&m_number, &a.m_number);
    }

    bool isZero() const
    {
        return BN_is_zero(&m_number);
    }

    void Div(const plBigNum& a, uint32_t b, uint32_t* remainder)
    {
        // this = a / b, remainder = a % b
        BN_copy(&m_number, &a.m_number);
        *remainder = (uint32_t)BN_div_word(&m_number, b);
    }

    void Div(const plBigNum& a, const plBigNum& b, plBigNum* remainder)
    {
        // this = a / b, remainder = a % b
        // either this or remainder may be nil
        BN_div(this ? &m_number : nil, remainder ? &remainder->m_number : nil,
               &a.m_number, &b.m_number, GetContext());
    }

    void FromData_BE(uint32_t bytess, const void* data)
    {
        BN_bin2bn((const uint8_t*)data, bytess, &m_number);
    }

    void FromData_LE(uint32_t bytess, const void* data);

    uint8_t* GetData_BE(uint32_t* bytess) const;
    uint8_t* GetData_LE(uint32_t* bytess) const;

    bool IsPrime() const
    {
        // Cyan's code uses 3 checks, so we'll follow suit.
        // This provides an accurate answer to p < 0.015625
        return BN_is_prime_fasttest(&m_number, 3, nil, GetContext(), nil, 1) > 0;
    }

    void Mod(const plBigNum& a, const plBigNum& b)
    {
        // this = a % b
        BN_div(nil, &m_number, &a.m_number, &b.m_number, GetContext());
    }

    void Mul(const plBigNum& a, uint32_t b)
    {
        // this = a * b
        BN_copy(&m_number, &a.m_number);
        BN_mul_word(&m_number, b);
    }

    void Mul(const plBigNum& a, const plBigNum& b)
    {
        // this = a * b
        BN_mul(&m_number, &a.m_number, &b.m_number, GetContext());
    }

    void PowMod(uint32_t a, const plBigNum& b, const plBigNum& c)
    {
        // this = a ^ b % c
        PowMod(plBigNum(a), b, c);
    }

    void PowMod(const plBigNum& a, const plBigNum& b, const plBigNum& c)
    {
        // this = a ^ b % c
        BN_mod_exp(&m_number, &a.m_number, &b.m_number, &c.m_number, GetContext());
    }

    void Rand(const plBigNum& a, plBigNum* seed)
    {
        // this = random number less than a
        int bits = BN_num_bits(&a.m_number);
        do
            Rand(bits, seed);
        while (Compare(a) >= 0);
    }

    void Rand(uint32_t bits, plBigNum* seed);

    void RandPrime(uint32_t bits, plBigNum* seed)
    {
        BN_generate_prime(&m_number, bits, 1, nil, nil, nil, nil);
    }

    void Set(const plBigNum& a)
    {
        BN_copy(&m_number, &a.m_number);
    }

    void Set(uint32_t a)
    {
        BN_set_word(&m_number, a);
    }

    void SetOne() { Set(1); }
    void SetZero() { Set(0); }

    void Shl(const plBigNum& a, uint32_t b)
    {
        // this = a << b
        BN_lshift(&m_number, &a.m_number, b);
    }

    void Shr(const plBigNum& a, uint32_t b)
    {
        // this = a >> b
        BN_rshift(&m_number, &a.m_number, b);
    }

    void Sub(const plBigNum& a, uint32_t b)
    {
        // this = a - b
        BN_copy(&m_number, &a.m_number);
        BN_sub_word(&m_number, b);
    }

    void Sub(const plBigNum& a, const plBigNum& b)
    {
        // this = a - b
        BN_sub(&m_number, &a.m_number, &b.m_number);
    }
};
#endif // plBigNum_inc