#include <client.h>

Public Member Functions
	Client (const std::shared_ptr< ServiceProvider > &serviceProvider, const std::shared_ptr< PrivacyServiceProvider > &privacyServiceProvider, const PaillierPublicKey &publicKey)
	Constructor. More...

	~Client ()
	Destructor - void implementation.

const ServiceProvider::EncryptedUserDataContainer &	GetNormalizedScaledRatings () const
	Get \( [\tilde{V}_i^d] \). More...

const ServiceProvider::PackedItems &	GetSparseRatings () const
	Get \( [V_i^{Packed}] \). More...

void	ComputeRecommendations ()
	Interact with the server(s) to extract the recommendations for every user. More...

Private Types
typedef DecryptionBlindingFactorContainer < Paillier, BlindingFactorCacheParameters >	BlindingFactorContainer
	Alias for the blinding factor container.

Private Member Functions
std::deque< BigInteger >	computeEmptyBuckets (const size_t L) const
	Computes the empty buckets \( 2^{i * bucketSize} \). More...

ServiceProvider::PackedData	packUserSparseRatings (const std::deque< unsigned long > &userPlaintextSparseRatings, const std::deque< BigInteger > &userEmptyBuckets) const
	Pack the sparse ratings for one user. More...

	Client (Client const &)
	Copy constructor - not implemented.

Client	operator= (Client const &)
	Copy assignment operator - not implemented.

Private Attributes
const std::shared_ptr < ServiceProvider >	serviceProvider
	A reference to the ServiceProvider.

const std::shared_ptr < PrivacyServiceProvider >	privacyServiceProvider
	A reference to the PrivacyServiceProvider.

Paillier	paillierCryptoProvider
	Paillier crypto provider.

size_t	userCount
	Number of users who need recommendations.

size_t	itemCount
	Number of ratings per user.

size_t	denselyRatedItemCount
	Number of densely rated items.

size_t	ratingBitSize
	The size of the user ratings (in bits)

size_t	scaledNormalizedRatingBitSize
	k - The size of the scaled normalized ratings (in bits)

unsigned int	digitsToPreserve
	Number of digits preserved from the normalized user ratings.

size_t	kappa
	The security parameter for the secure comparison protocol (in bits)

size_t	hatL
	The upper bound of most similar users ( \( \hat{L} > L \))

std::deque< BigInteger >	emptyBuckets
	Empty buckets \( (2^{t + \lceil\log{\hat{L}}\rceil})^i \), where \( t \) is the bit size of the ratings.

std::string	ratingsFilePath
	The path to the file containing precomputed ratings.

ServiceProvider::EncryptedUserDataContainer	normalizedScaledRatings
	\( [\tilde{V}_i^d] \)

std::deque< std::deque < unsigned long > >	plaintextSparseRatings
	\( V_i^p \)

ServiceProvider::PackedItems	sparseRatings
	\( [V_i^{Packed}] \)

RandomizerCache < BlindingFactorContainer >	LdecryptionBlindingFactorCache
	\( L \) decryption blinding factor cache instance

RandomizerCache < BlindingFactorContainer >	URSumDecryptionBlindingFactorCache
	\( UR^{sum} \) decryption blinding factor cache instance

Static Private Attributes
static const std::string	configurationPath
	Service Provider configuration path. More...

Detailed Description

Client.

Definition at line 62 of file private_recommendations_data_packing/client.h.

Constructor & Destructor Documentation

SeComLib::PrivateRecommendationsDataPacking::Client::Client	(	const std::shared_ptr< ServiceProvider > &	serviceProvider,
		const std::shared_ptr< PrivacyServiceProvider > &	privacyServiceProvider,
		const PaillierPublicKey &	publicKey
	)

Constructor.

Assumes that the client has a secure channel to the PrivacyServiceProvider.

Parameters

serviceProvider	a ServiceProvider instance
privacyServiceProvider	a PrivacyServiceProvider instance
publicKey	the Paillier public key of the PrivacyServiceProvider

Exceptions

std::runtime_error the ratings file can't be opened

Compute the empty buckets first

Load ratings from file

Pack the sparse ratings

Definition at line 48 of file private_recommendations_data_packing/client.cpp.

Member Function Documentation

std::deque< BigInteger > SeComLib::PrivateRecommendationsDataPacking::Client::computeEmptyBuckets ( const size_t L ) const

private

Computes the empty buckets \( 2^{i * bucketSize} \).

Parameters

L	the number of similar users

Returns: the empty buckets

Precompute \( \lceil log_2(\hat{L}) \rceil \) and initialize the sparse ratings data packer

\( t + \lceil\log{\hat{L}}\rceil \)

We need to reserve \( \kappa \) extra bits in each encryption in order to perform secure blinding In order not to cause overflows during secure blinding, we reserve another 2 extra bits at the top of each encryption, such that if size(r) = size(message space) - 2, then r + d < message space

Pre-compute the empty buckets \( 2^{i * bucketSize} \)

Definition at line 262 of file private_recommendations_data_packing/client.cpp.

void SeComLib::PrivateRecommendationsDataPacking::Client::ComputeRecommendations ( )

Interact with the server(s) to extract the recommendations for every user.

Fetches encrypted values from the Service Provider, blinds them and sends them to the Privacy Service Provider for decryption.

Fetch \( [L] \) and \( [UR_{sum}] \) from the Service Provider

\( L = Dec([L][r]) - r \)

If \( L < \hat{L} \) the server computed the proper recommendations

If \( L >= \hat{L} \) the sparse ratings need to be repacked and sent to the server in order to recompute the recommendations

Unpack \( UR_{sum} \)

\( UR_{sum} = Dec([UR_{sum}][r]) - r \)

There are (items - denselyRelatedItems) packed buckets in total, so the last encryption may have unpopulated buckets, which we ignore

Definition at line 170 of file private_recommendations_data_packing/client.cpp.

const ServiceProvider::EncryptedUserDataContainer & SeComLib::PrivateRecommendationsDataPacking::Client::GetNormalizedScaledRatings ( ) const

Get \( [\tilde{V}_i^d] \).

Returns: \( [\tilde{V}_i^d] \)

Definition at line 156 of file private_recommendations_data_packing/client.cpp.

const ServiceProvider::PackedItems & SeComLib::PrivateRecommendationsDataPacking::Client::GetSparseRatings ( ) const

Get \( [V_i^{Packed}] \).

Returns: \( [V_i^{Packed}] \)

Definition at line 163 of file private_recommendations_data_packing/client.cpp.

ServiceProvider::PackedData SeComLib::PrivateRecommendationsDataPacking::Client::packUserSparseRatings	(	const std::deque< unsigned long > &	userPlaintextSparseRatings,
		const std::deque< BigInteger > &	userEmptyBuckets
	)		const

private

Pack the sparse ratings for one user.

Parameters

userPlaintextSparseRatings	the plaintext sparse ratings
userEmptyBuckets	the empty buckets

Returns: packed user sparse ratings

Definition at line 291 of file private_recommendations_data_packing/client.cpp.

Member Data Documentation

const std::string SeComLib::PrivateRecommendationsDataPacking::Client::configurationPath

staticprivate

Service Provider configuration path.

Set the configuration path.

Definition at line 94 of file private_recommendations_data_packing/client.h.

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

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation