Class that provides the functionality for the linear transforms used in boostrapping. The constructor is invoked with three arguments: More...

#include <EvalMap.h>

Public Member Functions
	EvalMap (const EncryptedArray &_ea, bool minimal, const NTL::Vec< long > &mvec, bool _invert, bool build_cache, bool normal_basis=true)

void	upgrade ()

void	apply (Ctxt &ctxt) const

Detailed Description

Class that provides the functionality for the linear transforms used in boostrapping. The constructor is invoked with three arguments:

an EncryptedArray object ea
an integer vector mvec
a boolean flag invert The mvec vector specifies the factorization of m to use in the "powerful basis" decomposition.

If the invert flag is false, the forward transformation is used. This transformation views the slots as being packed with powerful-basis coefficients and performs a multi-point polynomial evaluation. This is the second transformation used in bootstrapping.

If invert flag is true, the inverse transformation is used. In addition, the current implementation folds into the inverse transformation a transformation that moves the coefficients in each slot into a normal-basis representation, which helps with the unpacking procedure.

The constructor precomputes certain values, and the linear transformation itself is effected using the apply method.

Note that the factorization in mvec must correspond to the generators used in PAlgebra. The best way to ensure this is to directly use the output of the program in params.cpp: that program computes values for mvec (to be used here), and gens and ords (to be used in initialization of the Context).

Constructor & Destructor Documentation

◆ EvalMap()

helib::EvalMap::EvalMap	(	const EncryptedArray &	_ea,
		bool	minimal,
		const NTL::Vec< long > &	mvec,
		bool	_invert,
		bool	build_cache,
		bool	normal_basis = `true`
	)

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ EvalMap()

Member Function Documentation

◆ apply()

◆ upgrade()