Botan::Kyber_PublicKeyInternal Class Reference

#include <kyber_keys.h>

Public Member Functions
const KyberHashedPublicKey &	H_public_key_bits_raw () const
KyberCompressedCiphertext	indcpa_encrypt (const KyberMessage &m, const KyberEncryptionRandomness &r, const KyberPolyMat &At) const
void	indcpa_encrypt (StrongSpan< KyberCompressedCiphertext > out_ct, StrongSpan< const KyberMessage > m, StrongSpan< const KyberEncryptionRandomness > r, const KyberPolyMat &At) const
	Kyber_PublicKeyInternal ()=delete
	Kyber_PublicKeyInternal (KyberConstants mode, KyberPolyVecNTT polynomials, KyberSeedRho seed)
	Kyber_PublicKeyInternal (KyberConstants mode, KyberSerializedPublicKey public_key)
const KyberConstants &	mode () const
const KyberSerializedPublicKey &	public_key_bits_raw () const
const KyberSeedRho &	rho () const
const KyberPolyVecNTT &	t () const

Detailed Description

Definition at line 29 of file kyber_keys.h.

Constructor & Destructor Documentation

Kyber_PublicKeyInternal() [1/3]

Botan::Kyber_PublicKeyInternal::Kyber_PublicKeyInternal	(	KyberConstants	mode,
		KyberSerializedPublicKey	public_key )

Definition at line 30 of file kyber_keys.cpp.

                                                                                                         :
      m_mode(std::move(mode)),
      m_public_key_bits_raw(validate_public_key_length(std::move(public_key), m_mode.public_key_bytes())),
      m_H_public_key_bits_raw(m_mode.symmetric_primitives().H(m_public_key_bits_raw)),
      m_t(Kyber_Algos::decode_polynomial_vector(
         std::span{m_public_key_bits_raw}.first(m_mode.polynomial_vector_bytes()), m_mode)),
      m_rho(std::span{m_public_key_bits_raw}.last(Botan::KyberConstants::SEED_BYTES)) {}

Kyber_PublicKeyInternal() [2/3]

Botan::Kyber_PublicKeyInternal::Kyber_PublicKeyInternal	(	KyberConstants	mode,
		KyberPolyVecNTT	polynomials,
		KyberSeedRho	seed )

Definition at line 38 of file kyber_keys.cpp.

                                                                                                         :
      m_mode(std::move(mode)),
      m_public_key_bits_raw(concat(Kyber_Algos::encode_polynomial_vector<std::vector<uint8_t>>(t, m_mode), rho)),
      m_H_public_key_bits_raw(m_mode.symmetric_primitives().H(m_public_key_bits_raw)),
      m_t(std::move(t)),
      m_rho(std::move(rho)) {}

Kyber_PublicKeyInternal() [3/3]

Botan::Kyber_PublicKeyInternal::Kyber_PublicKeyInternal ( )

delete

Member Function Documentation

H_public_key_bits_raw()

const KyberHashedPublicKey & Botan::Kyber_PublicKeyInternal::H_public_key_bits_raw ( ) const

inline

Definition at line 55 of file kyber_keys.h.

{ return m_H_public_key_bits_raw; }

indcpa_encrypt() [1/2]

KyberCompressedCiphertext Botan::Kyber_PublicKeyInternal::indcpa_encrypt ( const KyberMessage & m, const KyberEncryptionRandomness & r, const KyberPolyMat & At ) const

inline

Definition at line 39 of file kyber_keys.h.

                                                                             {
         KyberCompressedCiphertext ct(m_mode.ciphertext_bytes());
         indcpa_encrypt(ct, m, r, At);
         return ct;
      }

References Botan::KyberConstants::ciphertext_bytes(), and indcpa_encrypt().

indcpa_encrypt() [2/2]

void Botan::Kyber_PublicKeyInternal::indcpa_encrypt	(	StrongSpan< KyberCompressedCiphertext >	out_ct,
		StrongSpan< const KyberMessage >	m,
		StrongSpan< const KyberEncryptionRandomness >	r,
		const KyberPolyMat &	At ) const

NIST FIPS 203, Algorithm 14 (K-PKE.Encrypt)

In contrast to FIPS 203, the matrix At is not sampled for every invocation, instead it is precomputed and passed in as a parameter. Similarly, the t^T is already decoded and available as a member variable. This allows to reuse these structures for multiple encryptions.

The sampling loops spelled out in FIPS 203 are hidden in the sample_* functions.

Definition at line 55 of file kyber_keys.cpp.

                                                                           {
   // The nonce N is handled internally by the PolynomialSampler
   Kyber_Algos::PolynomialSampler ps(r, m_mode);
   const auto y = ntt(ps.sample_polynomial_vector_cbd_eta1());
   const auto e1 = ps.sample_polynomial_vector_cbd_eta2();
   const auto e2 = ps.sample_polynomial_cbd_eta2();
 
   auto u = inverse_ntt(At * y);
   u += e1;
   u.reduce();
 
   const auto mu = Kyber_Algos::polynomial_from_message(m);
   auto v = inverse_ntt(m_t * y);
   v += e2;
   v += mu;
   v.reduce();
 
   Kyber_Algos::compress_ciphertext(out_ct, u, v, m_mode);
}

References Botan::Kyber_Algos::compress_ciphertext(), Botan::Kyber_Algos::polynomial_from_message(), Botan::Kyber_Algos::PolynomialSampler< SeedT >::sample_polynomial_cbd_eta2(), Botan::Kyber_Algos::PolynomialSampler< SeedT >::sample_polynomial_vector_cbd_eta1(), and Botan::Kyber_Algos::PolynomialSampler< SeedT >::sample_polynomial_vector_cbd_eta2().

Referenced by indcpa_encrypt().

mode()

const KyberConstants & Botan::Kyber_PublicKeyInternal::mode ( ) const

inline

Definition at line 51 of file kyber_keys.h.

{ return m_mode; }

public_key_bits_raw()

const KyberSerializedPublicKey & Botan::Kyber_PublicKeyInternal::public_key_bits_raw ( ) const

inline

Definition at line 53 of file kyber_keys.h.

{ return m_public_key_bits_raw; }

rho()

const KyberSeedRho & Botan::Kyber_PublicKeyInternal::rho ( ) const

inline

Definition at line 49 of file kyber_keys.h.

{ return m_rho; }

t()

const KyberPolyVecNTT & Botan::Kyber_PublicKeyInternal::t ( ) const

inline

Definition at line 47 of file kyber_keys.h.

{ return m_t; }

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

• src/lib/pubkey/kyber/kyber_common/kyber_keys.h
• src/lib/pubkey/kyber/kyber_common/kyber_keys.cpp