Struct Plaintext 

pub struct Plaintext { /* private fields */ }

Class to store a plaintext encoded items. The data encoded for the plaintext is a polynomial with coefficients modulo the plaintext modulus. The degree of the plaintext polynomial must be one less than the degree of the polynomial modulus. The backing array always allocates one 64-bit word per each coefficient of the polynomial.

Memory Management

The coefficient count of a plaintext refers to the number of word-size coefficients in the plaintext, whereas its capacity refers to the number of word-size coefficients that fit in the current memory allocation. In high-performance applications unnecessary re-allocations should be avoided by reserving enough memory for the plaintext to begin with either by providing the desired capacity to the constructor as an extra argument, or by calling the reserve function at any time.

When the scheme is SchemeType.BFV each coefficient of a plaintext is a 64-bit word, but when the scheme is SchemeType.CKKS the plaintext is by default stored in an NTT transformed form with respect to each of the primes in the coefficient modulus. Thus, the size of the allocation that is needed is the size of the coefficient modulus (number of primes) times the degree of the polynomial modulus. In addition, a valid CKKS plaintext will also store the ParmsId for the corresponding encryption parameters.

Implementations

impl Plaintext

pub fn new() -> Result<Self>

Constructs an empty plaintext allocating no memory.

pub fn new_with_pool(memory: &MemoryPool) -> Result<Self>

Constructs an empty plaintext in a memory pool.

pub fn from_hex_string(hex_str: &str) -> Result<Self>

Constructs a plaintext from a given hexadecimal string describing the plaintext polynomial.

The string description of the polynomial must adhere to the format returned by ToString(), which is of the form “7FFx^3 + 1x^1 + 3” and summarized by the following rules:

1. Terms are listed in order of strictly decreasing exponent
2. Coefficient values are non-negative and in hexadecimal format (upper and lower case letters are both supported)
3. Exponents are positive and in decimal format
4. Zero coefficient terms (including the constant term) may be (but do not have to be) omitted
5. Term with the exponent value of one must be exactly written as x^1
6. Term with the exponent value of zero (the constant term) must be written as just a hexadecimal number without exponent
7. Terms must be separated by exactly [space]+[space] and minus is not allowed
8. Other than the +, no other terms should have whitespace

• hex_str: The formatted polynomial string specifying the plaintext polynomial.

Panics

Panics if hex_str contains a null character anywhere but the end of the string.

pub fn get_coefficient(&self, index: usize) -> u64

Gets the coefficient at the given location. Coefficients are ordered from lowest to highest degree, with the first value being the constant coefficient.

Panics

Panics if index is greater than len().

pub fn set_coefficient(&mut self, index: usize, value: u64)

Sets the coefficient at the given location. Coefficients are ordered from lowest to highest degree, with the first value being the constant coefficient.

Panics

Panics if index is greater than len().

pub fn resize(&mut self, count: usize)

Sets the number of coefficients this plaintext can hold.

pub fn len(&self) -> usize

Returns the number of coefficients this plaintext can hold.

pub fn is_empty(&self) -> bool

Returns true if the plaintext is empty.

pub fn is_ntt_form(&self) -> bool

Returns whether the plaintext is in NTT form.

Trait Implementations

impl AsRef<Plaintext> for Plaintext

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for Plaintext

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Plaintext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for Plaintext

fn drop(&mut self)

Executes the destructor for this type.

impl FromBytes for Plaintext

fn from_bytes(context: &Context, data: &[u8]) -> Result<Self>

Deserializes a byte stream into a plaintext. This requires a context, which is why Plaintext doesn’t impl Deserialize.

type State = Context

State used to deserialize an object from bytes.

impl Hash for Plaintext

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Plaintext

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Plaintext

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl ToBytes for Plaintext

fn as_bytes(&self) -> Result<Vec<u8>>

Returns the object as a byte array.