Botan::AffineCurvePoint< FieldElement, Params > Class Template Reference

#include <pcurves_impl.h>

Public Types
using	Self = AffineCurvePoint<FieldElement, Params>

Public Member Functions
constexpr	AffineCurvePoint ()
constexpr	AffineCurvePoint (const FieldElement &x, const FieldElement &y)
	AffineCurvePoint (const Self &other)=default
	AffineCurvePoint (Self &&other)=default
constexpr void	conditional_assign (CT::Choice cond, const Self &pt)
constexpr void	ct_poison () const
constexpr void	ct_unpoison () const
constexpr CT::Choice	is_identity () const
constexpr Self	negate () const
AffineCurvePoint &	operator= (const Self &other)=default
AffineCurvePoint &	operator= (Self &&other)=default
constexpr void	serialize_compressed_to (std::span< uint8_t, Self::COMPRESSED_BYTES > bytes) const
constexpr void	serialize_to (std::span< uint8_t, Self::BYTES > bytes) const
constexpr const FieldElement &	x () const
constexpr const FieldElement &	y () const

Static Public Member Functions
static constexpr auto	ct_select (std::span< const Self > pts, size_t idx)
static constexpr std::optional< Self >	deserialize (std::span< const uint8_t > bytes)
static constexpr Self	identity ()
static constexpr FieldElement	x3_ax_b (const FieldElement &x)

Static Public Attributes
static constexpr FieldElement	A = FieldElement::from_words(Params::AW)
static constexpr FieldElement	B = FieldElement::from_words(Params::BW)
static constexpr size_t	BYTES = 1 + 2 * FieldElement::BYTES
static constexpr size_t	COMPRESSED_BYTES = 1 + FieldElement::BYTES

Detailed Description

template<typename FieldElement, typename Params>
class Botan::AffineCurvePoint< FieldElement, Params >

Definition at line 416 of file pcurves_impl.h.

Member Typedef Documentation

Self

template<typename FieldElement , typename Params >

using Botan::AffineCurvePoint< FieldElement, Params >::Self = AffineCurvePoint<FieldElement, Params>

Definition at line 427 of file pcurves_impl.h.

Constructor & Destructor Documentation

AffineCurvePoint() [1/4]

template<typename FieldElement , typename Params >

Botan::AffineCurvePoint< FieldElement, Params >::AffineCurvePoint ( const FieldElement & x, const FieldElement & y )

inlineconstexpr

Definition at line 429 of file pcurves_impl.h.

: m_x(x), m_y(y) {}

AffineCurvePoint() [2/4]

template<typename FieldElement , typename Params >

Botan::AffineCurvePoint< FieldElement, Params >::AffineCurvePoint ( )

inlineconstexpr

Definition at line 431 of file pcurves_impl.h.

: m_x(FieldElement::zero()), m_y(FieldElement::zero()) {}

AffineCurvePoint() [3/4]

template<typename FieldElement , typename Params >

Botan::AffineCurvePoint< FieldElement, Params >::AffineCurvePoint ( const Self & other )

default

AffineCurvePoint() [4/4]

template<typename FieldElement , typename Params >

Botan::AffineCurvePoint< FieldElement, Params >::AffineCurvePoint ( Self && other )

default

Member Function Documentation

conditional_assign()

template<typename FieldElement , typename Params >

void Botan::AffineCurvePoint< FieldElement, Params >::conditional_assign ( CT::Choice cond, const Self & pt )

inlineconstexpr

Definition at line 520 of file pcurves_impl.h.

                                                                       {
         m_x.conditional_assign(cond, pt.x());
         m_y.conditional_assign(cond, pt.y());
      }

References Botan::AffineCurvePoint< FieldElement, Params >::x(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

ct_poison()

template<typename FieldElement , typename Params >

void Botan::AffineCurvePoint< FieldElement, Params >::ct_poison ( ) const

inlineconstexpr

Definition at line 525 of file pcurves_impl.h.

                                       {
         x().ct_poison();
         y().ct_poison();
      }

References Botan::AffineCurvePoint< FieldElement, Params >::x(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

ct_select()

template<typename FieldElement , typename Params >

static constexpr auto Botan::AffineCurvePoint< FieldElement, Params >::ct_select ( std::span< const Self > pts, size_t idx )

inlinestaticconstexpr

If idx is zero then return the identity element. Otherwise return pts[idx - 1]

Returns the identity element also if idx is out of range

Definition at line 466 of file pcurves_impl.h.

                                                                           {
         auto result = Self::identity();
 
         // Intentionally wrapping; set to maximum size_t if idx == 0
         const size_t idx1 = static_cast<size_t>(idx - 1);
         for(size_t i = 0; i != pts.size(); ++i) {
            const auto found = CT::Mask<size_t>::is_equal(idx1, i).as_choice();
            result.conditional_assign(found, pts[i]);
         }
 
         return result;
      }

References Botan::AffineCurvePoint< FieldElement, Params >::identity(), and Botan::CT::Mask< T >::is_equal().

ct_unpoison()

template<typename FieldElement , typename Params >

void Botan::AffineCurvePoint< FieldElement, Params >::ct_unpoison ( ) const

inlineconstexpr

Definition at line 530 of file pcurves_impl.h.

                                         {
         x().ct_unpoison();
         y().ct_unpoison();
      }

References Botan::AffineCurvePoint< FieldElement, Params >::x(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

deserialize()

template<typename FieldElement , typename Params >

static constexpr std::optional< Self > Botan::AffineCurvePoint< FieldElement, Params >::deserialize ( std::span< const uint8_t > bytes )

inlinestaticconstexpr

Definition at line 481 of file pcurves_impl.h.

                                                                                   {
         if(bytes.size() == Self::BYTES) {
            if(bytes[0] != 0x04) {
               return {};
            }
            auto x = FieldElement::deserialize(bytes.subspan(1, FieldElement::BYTES));
            auto y = FieldElement::deserialize(bytes.subspan(1 + FieldElement::BYTES, FieldElement::BYTES));
 
            if(x && y) {
               const auto lhs = (*y).square();
               const auto rhs = Self::x3_ax_b(*x);
               if((lhs == rhs).as_bool()) {
                  return Self(*x, *y);
               }
            }
 
            return {};
         } else if(bytes.size() == Self::COMPRESSED_BYTES) {
            if(bytes[0] != 0x02 && bytes[0] != 0x03) {
               return {};
            }
            const CT::Choice y_is_even = CT::Mask<uint8_t>::is_equal(bytes[0], 0x02).as_choice();
 
            if(auto x = FieldElement::deserialize(bytes.subspan(1, FieldElement::BYTES))) {
               auto y = x3_ax_b(*x).sqrt();
               y.conditional_assign(y_is_even && !y.is_even(), y.negate());
               return Self(*x, y);
            }
 
            return {};
         } else {
            return {};
         }
      }

References Botan::AffineCurvePoint< FieldElement, Params >::BYTES, Botan::AffineCurvePoint< FieldElement, Params >::COMPRESSED_BYTES, Botan::CT::Mask< T >::is_equal(), Botan::AffineCurvePoint< FieldElement, Params >::x(), Botan::AffineCurvePoint< FieldElement, Params >::x3_ax_b(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

identity()

template<typename FieldElement , typename Params >

static constexpr Self Botan::AffineCurvePoint< FieldElement, Params >::identity ( )

inlinestaticconstexpr

Definition at line 433 of file pcurves_impl.h.

{ return Self(FieldElement::zero(), FieldElement::zero()); }

Referenced by Botan::AffineCurvePoint< FieldElement, Params >::ct_select(), Botan::ProjectiveCurvePoint< FieldElement, Params >::to_affine(), and Botan::ProjectiveCurvePoint< FieldElement, Params >::to_affine_batch().

is_identity()

template<typename FieldElement , typename Params >

CT::Choice Botan::AffineCurvePoint< FieldElement, Params >::is_identity ( ) const

inlineconstexpr

Definition at line 435 of file pcurves_impl.h.

{ return x().is_zero() && y().is_zero(); }

References Botan::AffineCurvePoint< FieldElement, Params >::x(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

Referenced by Botan::ProjectiveCurvePoint< FieldElement, Params >::add_mixed(), and Botan::ProjectiveCurvePoint< FieldElement, Params >::from_affine().

negate()

template<typename FieldElement , typename Params >

Self Botan::AffineCurvePoint< FieldElement, Params >::negate ( ) const

inlineconstexpr

Definition at line 442 of file pcurves_impl.h.

{ return Self(x(), y().negate()); }

References Botan::AffineCurvePoint< FieldElement, Params >::negate(), Botan::AffineCurvePoint< FieldElement, Params >::x(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

Referenced by Botan::AffineCurvePoint< FieldElement, Params >::negate().

operator=() [1/2]

template<typename FieldElement , typename Params >

AffineCurvePoint & Botan::AffineCurvePoint< FieldElement, Params >::operator= ( const Self & other )

default

operator=() [2/2]

template<typename FieldElement , typename Params >

AffineCurvePoint & Botan::AffineCurvePoint< FieldElement, Params >::operator= ( Self && other )

default

serialize_compressed_to()

template<typename FieldElement , typename Params >

void Botan::AffineCurvePoint< FieldElement, Params >::serialize_compressed_to ( std::span< uint8_t, Self::COMPRESSED_BYTES > bytes ) const

inlineconstexpr

Definition at line 452 of file pcurves_impl.h.

                                                                                                 {
         const uint8_t hdr = CT::Mask<uint8_t>::from_choice(y().is_even()).select(0x02, 0x03);
 
         BufferStuffer pack(bytes);
         pack.append(hdr);
         x().serialize_to(pack.next<FieldElement::BYTES>());
         BOTAN_DEBUG_ASSERT(pack.full());
      }

References Botan::BufferStuffer::append(), BOTAN_DEBUG_ASSERT, Botan::CT::Mask< T >::from_choice(), Botan::BufferStuffer::full(), Botan::BufferStuffer::next(), Botan::AffineCurvePoint< FieldElement, Params >::x(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

serialize_to()

template<typename FieldElement , typename Params >

void Botan::AffineCurvePoint< FieldElement, Params >::serialize_to ( std::span< uint8_t, Self::BYTES > bytes ) const

inlineconstexpr

Definition at line 444 of file pcurves_impl.h.

                                                                           {
         BufferStuffer pack(bytes);
         pack.append(0x04);
         x().serialize_to(pack.next<FieldElement::BYTES>());
         y().serialize_to(pack.next<FieldElement::BYTES>());
         BOTAN_DEBUG_ASSERT(pack.full());
      }

References Botan::BufferStuffer::append(), BOTAN_DEBUG_ASSERT, Botan::BufferStuffer::full(), Botan::BufferStuffer::next(), Botan::AffineCurvePoint< FieldElement, Params >::x(), and Botan::AffineCurvePoint< FieldElement, Params >::y().

x()

template<typename FieldElement , typename Params >

const FieldElement & Botan::AffineCurvePoint< FieldElement, Params >::x ( ) const

inlineconstexpr

Definition at line 516 of file pcurves_impl.h.

{ return m_x; }

Referenced by Botan::ProjectiveCurvePoint< FieldElement, Params >::add_mixed(), Botan::AffineCurvePoint< FieldElement, Params >::conditional_assign(), Botan::AffineCurvePoint< FieldElement, Params >::ct_poison(), Botan::AffineCurvePoint< FieldElement, Params >::ct_unpoison(), Botan::AffineCurvePoint< FieldElement, Params >::deserialize(), Botan::ProjectiveCurvePoint< FieldElement, Params >::from_affine(), Botan::AffineCurvePoint< FieldElement, Params >::is_identity(), Botan::AffineCurvePoint< FieldElement, Params >::negate(), Botan::AffineCurvePoint< FieldElement, Params >::serialize_compressed_to(), Botan::AffineCurvePoint< FieldElement, Params >::serialize_to(), and Botan::AffineCurvePoint< FieldElement, Params >::x3_ax_b().

x3_ax_b()

template<typename FieldElement , typename Params >

static constexpr FieldElement Botan::AffineCurvePoint< FieldElement, Params >::x3_ax_b ( const FieldElement & x )

inlinestaticconstexpr

Definition at line 479 of file pcurves_impl.h.

{ return (x.square() + Self::A) * x + Self::B; }

References Botan::AffineCurvePoint< FieldElement, Params >::A, Botan::AffineCurvePoint< FieldElement, Params >::B, and Botan::AffineCurvePoint< FieldElement, Params >::x().

Referenced by Botan::AffineCurvePoint< FieldElement, Params >::deserialize().

y()

template<typename FieldElement , typename Params >

const FieldElement & Botan::AffineCurvePoint< FieldElement, Params >::y ( ) const

inlineconstexpr

Definition at line 518 of file pcurves_impl.h.

{ return m_y; }

Referenced by Botan::ProjectiveCurvePoint< FieldElement, Params >::add_mixed(), Botan::AffineCurvePoint< FieldElement, Params >::conditional_assign(), Botan::AffineCurvePoint< FieldElement, Params >::ct_poison(), Botan::AffineCurvePoint< FieldElement, Params >::ct_unpoison(), Botan::AffineCurvePoint< FieldElement, Params >::deserialize(), Botan::ProjectiveCurvePoint< FieldElement, Params >::from_affine(), Botan::AffineCurvePoint< FieldElement, Params >::is_identity(), Botan::AffineCurvePoint< FieldElement, Params >::negate(), Botan::AffineCurvePoint< FieldElement, Params >::serialize_compressed_to(), and Botan::AffineCurvePoint< FieldElement, Params >::serialize_to().

Member Data Documentation

A

template<typename FieldElement , typename Params >

FieldElement Botan::AffineCurvePoint< FieldElement, Params >::A = FieldElement::from_words(Params::AW)

staticconstexpr

Definition at line 421 of file pcurves_impl.h.

Referenced by Botan::AffineCurvePoint< FieldElement, Params >::x3_ax_b().

B

template<typename FieldElement , typename Params >

FieldElement Botan::AffineCurvePoint< FieldElement, Params >::B = FieldElement::from_words(Params::BW)

staticconstexpr

Definition at line 422 of file pcurves_impl.h.

Referenced by Botan::AffineCurvePoint< FieldElement, Params >::x3_ax_b().

BYTES

template<typename FieldElement , typename Params >

size_t Botan::AffineCurvePoint< FieldElement, Params >::BYTES = 1 + 2 * FieldElement::BYTES

staticconstexpr

Definition at line 424 of file pcurves_impl.h.

Referenced by Botan::AffineCurvePoint< FieldElement, Params >::deserialize().

COMPRESSED_BYTES

template<typename FieldElement , typename Params >

size_t Botan::AffineCurvePoint< FieldElement, Params >::COMPRESSED_BYTES = 1 + FieldElement::BYTES

staticconstexpr

Definition at line 425 of file pcurves_impl.h.

Referenced by Botan::AffineCurvePoint< FieldElement, Params >::deserialize().

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The documentation for this class was generated from the following file:

• src/lib/math/pcurves/pcurves_impl.h