Used to perform operations on bitwise CTiles. More...

#include <BitwiseEvaluator.h>

Public Member Functions
BitwiseEvaluator (HeContext &he)
Constructs a ready to use object. More...

CTile getMSB (const CTile &c) const
Returns the MSB of c. More...

CTile getFlippedMSB (const CTile &c) const
Returns The NOT of the MSB of c. More...

void setIsSigned (CTile &c, bool val) const
Sets c to be signed if val is true, and unsigned otherwise. More...

bool getIsSigned (const CTile &c) const
Returns true if c is signed and false otherwise. More...

CTile hamming (const CTile &c, int from=0, int to=-1) const

std::vector< CTile > split (const CTile &c) const
Returns a vector of the bits of "c". More...

CTile combine (const std::vector< CTile > cs, int from=0, int to=-1, int bitsPerElement=1) const
Combines the given bitwise CTiles into one. More...

CTile isEqual (const CTile &c1, const CTile &c2) const
Checks whether c1 == c2. More...

CTile multiply (const CTile &c1, const CTile &c2, int targetBits=-1) const
Returns first "targetBits" LSBs of c1*c2. More...

CTile add (const CTile &c1, const CTile &c2, int targetBits=-1) const
Returns the first "targetBits" LSBs of c1 + c2. More...

CTile sub (const CTile &c1, const CTile &c2, int targetBits=-1) const
Returns the first "targetBits" LSBs of c1 - c2. More...

CTile multiplyBit (const CTile &c, const CTile &bit) const
Returns the result of multiplying all bits of c by the given "bit". More...

CTile bitwiseXor (const CTile &c1, const CTile &c2) const
Bitwise xor between c1 and c2. More...

int getNumBits (const CTile &c) const
Returns the number of bits of c. More...

void setNumBits (CTile &c, int bits) const
Updates c to contain "bits" bits. More...

int getDefaultNumBits () const
Returns the default number of bits to a CTile. More...

void debugPrintWithBinary (const CTile &c, const std::string &title, int maxElements=4, int verbose=0, std::ostream &out=std::cout) const
Prints debug info. More...

double getScale (const CTile &c) const
Returns the scale of c. More...

CTile max (const CTile &c1, const CTile &c2) const
Returns max(c1, c2). More...

CTile min (const CTile &c1, const CTile &c2) const
Returns min(c1, c2). More...

CTile isGreater (const CTile &c1, const CTile &c2) const
Checks whether c1 < c2. More...

CTile isLess (const CTile &c1, const CTile &c2) const
Checks whether c1 > c2. More...

CTile isGreaterEqual (const CTile &c1, const CTile &c2) const
Checks whether c1 >= c2. More...

CTile isLessEqual (const CTile &c1, const CTile &c2) const
Checks whether c1 <= c2. More...

Detailed Description

Used to perform operations on bitwise CTiles.

Can only be constructed by bitwise HeContext.

Constructor & Destructor Documentation

◆ BitwiseEvaluator()

helayers::BitwiseEvaluator::BitwiseEvaluator ( HeContext & he )

Constructs a ready to use object.

Parameters

[in] he the underlying context.

Member Function Documentation

◆ add()

CTile helayers::BitwiseEvaluator::add	(	const CTile &	c1,
		const CTile &	c2,
		int	targetBits = `-1`
	)		const

Returns the first "targetBits" LSBs of c1 + c2.

If one of c1 or c2 is signed, the returned CTile will be signed. Otherwise, the returned CTile will be unsigned.

Parameters

[in]	c1,c2	To add
[in]	targetBits	The number of the bits of the result. If -1, the result will contain. max(getNumBits(c1) + getNumBits(c2) + 1) bits.

Exceptions

runtime_error If the scales of c1 and c2 are different.

◆ bitwiseXor()

CTile helayers::BitwiseEvaluator::bitwiseXor	(	const CTile &	c1,
		const CTile &	c2
	)		const

Bitwise xor between c1 and c2.

I c1 is signed, the result will be signed. Otherwise, the result will be unsigned.

Parameters

[in] c1,c2 To perform bitwise xor between.

◆ combine()

CTile helayers::BitwiseEvaluator::combine	(	const std::vector< CTile >	cs,
		int	from = `0`,
		int	to = `-1`,
		int	bitsPerElement = `1`
	)		const

Combines the given bitwise CTiles into one.

Combines all the bitwise CTiles in cs[from] until cs[to] (inclusive) into one bitwise CTile containing the first "bitsPerElement" LSB bits of each ciphertext. The LSB of the result is the first bit of cs[from]. If "to" is -1, then all the ciphertexts in cs[from] until cs.end() are taken.

Parameters

[in]	cs	The bitwise CTiles to combine
[in]	from	The index to start combining from.
[in]	out	The index to combine until.
[in]	bitsPerElement	How many bits to take from each CTile in "cs".

◆ debugPrintWithBinary()

void helayers::BitwiseEvaluator::debugPrintWithBinary	(	const CTile &	c,
		const std::string &	title,
		int	maxElements = `4`,
		int	verbose = `0`,
		std::ostream &	out = `std::cout`
	)		const

Prints debug info.

Parameters

[in]	c	The CTile to print debug info about.
[in]	title	The title used to display the debug message.
[in]	maxElements	Maximal number of slots to debug-print.
[in]	verbose	Verbose used while printing.
[in,out]	out	The ostream to print to.

◆ getDefaultNumBits()

int helayers::BitwiseEvaluator::getDefaultNumBits ( ) const

Returns the default number of bits to a CTile.

This default number is taken from the HeContext this BitwiseEvaluator was initialized with.

◆ getFlippedMSB()

CTile helayers::BitwiseEvaluator::getFlippedMSB ( const CTile & c ) const

Returns The NOT of the MSB of c.

/// The result is returned as one-bit, unsigned bitwise CTile.

Parameters

[in] c The CTile to get its flipped MSB.

◆ getIsSigned()

bool helayers::BitwiseEvaluator::getIsSigned ( const CTile & c ) const

Returns true if c is signed and false otherwise.

Parameters

[in] c To check whether it is signed.

◆ getMSB()

CTile helayers::BitwiseEvaluator::getMSB ( const CTile & c ) const

Returns the MSB of c.

The result is returned is one-bit, unsigned bitwise CTile.

Parameters

[in] c The CTile to get its MSB.

◆ getNumBits()

int helayers::BitwiseEvaluator::getNumBits ( const CTile & c ) const

Returns the number of bits of c.

Parameters

[in] c To check its number of bits.

◆ getScale()

double helayers::BitwiseEvaluator::getScale ( const CTile & c ) const

Returns the scale of c.

Parameters

[in] c To get its scale.

◆ isEqual()

CTile helayers::BitwiseEvaluator::isEqual	(	const CTile &	c1,
		const CTile &	c2
	)		const

Checks whether c1 == c2.

Returns (an encryption of) 1 if c1 == c2, and (an encryption of) 0 otherwise. The result is returned is one-bit, unsigned, bitwise CTile.

Parameters

[in] c1,c2 To evaluate c1 == c2 on.

◆ isGreater()

CTile helayers::BitwiseEvaluator::isGreater	(	const CTile &	c1,
		const CTile &	c2
	)		const

Checks whether c1 < c2.

Returns (an encryption of) 1 if c1 < c2, and (an encryption of) 0 otherwise. The result is returned is one-bit, unsigned, bitwise CTile.

Parameters

[in] c1,c2 To evaluate c1 < c2 on.

◆ isGreaterEqual()

CTile helayers::BitwiseEvaluator::isGreaterEqual	(	const CTile &	c1,
		const CTile &	c2
	)		const

Checks whether c1 >= c2.

Returns (an encryption of) 1 if c1 >= c2, and (an encryption of) 0 otherwise. The result is returned is one-bit, unsigned, bitwise CTile.

Parameters

[in] c1,c2 To evaluate c1 >= c2 on.

◆ isLess()

CTile helayers::BitwiseEvaluator::isLess	(	const CTile &	c1,
		const CTile &	c2
	)		const

Checks whether c1 > c2.

Returns (an encryption of) 1 if c1 > c2, and (an encryption of) 0 otherwise. The result is returned is one-bit, unsigned, bitwise CTile.

Parameters

[in] c1,c2 To evaluate c1 > c2 on.

◆ isLessEqual()

CTile helayers::BitwiseEvaluator::isLessEqual	(	const CTile &	c1,
		const CTile &	c2
	)		const

Checks whether c1 <= c2.

Returns (an encryption of) 1 if c1 <= c2, and (an encryption of) 0 otherwise. The result is returned is one-bit, unsigned, bitwise CTile.

Parameters

[in] c1,c2 To evaluate c1 <= c2 on.

◆ max()

CTile helayers::BitwiseEvaluator::max	(	const CTile &	c1,
		const CTile &	c2
	)		const

Returns max(c1, c2).

Parameters

[in] c1,c2 To compute their maximum.

◆ min()

CTile helayers::BitwiseEvaluator::min	(	const CTile &	c1,
		const CTile &	c2
	)		const

Returns min(c1, c2).

Parameters

[in] c1,c2 To compute their maximum.

◆ multiply()

CTile helayers::BitwiseEvaluator::multiply	(	const CTile &	c1,
		const CTile &	c2,
		int	targetBits = `-1`
	)		const

Returns first "targetBits" LSBs of c1*c2.

If one of c1 or c2 is signed, the returned CTile will be signed. Otherwise, the returned CTile will be unsigned. The scale of the result is set to the product of c1's and c2's scales.

Parameters

[in]	c1,c2	To multiply.
[in]	targetBits	The number of the bits of the result. If -1, the result will contain getNumBits(c1) + getNumBits(c2) bits.

◆ multiplyBit()

CTile helayers::BitwiseEvaluator::multiplyBit	(	const CTile &	c,
		const CTile &	bit
	)		const

Returns the result of multiplying all bits of c by the given "bit".

Parameters

[in]	c	To multiply its bits by the given bit.
[in]	bit	To multiply c by.

◆ setIsSigned()

void helayers::BitwiseEvaluator::setIsSigned	(	CTile &	c,
		bool	val
	)		const

Sets c to be signed if val is true, and unsigned otherwise.

Note that changing c from signed to unsigned (or converse) will cause its value to change accordingly. The value of a signed CTile is interpreted using 2's complement method, and the value of an unsigned CTile is interpreted as an ordinary binary number.

Parameters

[in]	c	To set to signed/unsigned.
[in]	val	Whether to set c to signed or unsigned.

◆ setNumBits()

void helayers::BitwiseEvaluator::setNumBits	(	CTile &	c,
		int	bits
	)		const

Updates c to contain "bits" bits.

If getNumBits(c) > bits, then MSBs of c are removed until it contains only "bits" bits. If getNumBits(c) < bits and c is signed, then the MSB of c is added to c until it contains "bits" bits. If getNumBits(c) < bits and c is unsigned, then 0 is added to c until it contains "bits" bits.

Parameters

[in,out]	c	The CTile to update to contain "bits" bit.
[in]	bits	The number of bits c will contain.

◆ split()

vector< CTile > helayers::BitwiseEvaluator::split ( const CTile & c ) const

Returns a vector of the bits of "c".

Each bit is returned as a one-bit, unsigned bitwise CTile.

Parameters

[in] c The CTile to split.

◆ sub()

CTile helayers::BitwiseEvaluator::sub	(	const CTile &	c1,
		const CTile &	c2,
		int	targetBits = `-1`
	)		const

Returns the first "targetBits" LSBs of c1 - c2.

If one of c1 or c2 is signed, the returned CTile will be signed. Otherwise, the returned CTile will be unsigned.

Parameters

[in]	c1,c2	To subtract.
[in]	targetBits	The number of the bits of the result. If -1, the result will contain getNumBits(c1) bits.

Exceptions

runtime_error If the scales of c1 and c2 are different.

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

/opt/IBM/FHE-distro/ML-HElib/src/helayers/hebase/BitwiseEvaluator.h
/opt/IBM/FHE-distro/ML-HElib/src/helayers/hebase/BitwiseEvaluator.cpp

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Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ BitwiseEvaluator()

Member Function Documentation

◆ add()

◆ bitwiseXor()

◆ combine()

◆ debugPrintWithBinary()

◆ getDefaultNumBits()

◆ getFlippedMSB()

◆ getIsSigned()

◆ getMSB()

◆ getNumBits()

◆ getScale()

◆ isEqual()

◆ isGreater()

◆ isGreaterEqual()

◆ isLess()

◆ isLessEqual()

◆ max()

◆ min()

◆ multiply()

◆ multiplyBit()

◆ setIsSigned()

◆ setNumBits()

◆ split()

◆ sub()