schemelet_get_element_params: RLWE encryption under a CKKS secret key

In openfhe.R: R Interface to the 'OpenFHE' Fully Homomorphic Encryption Library

RLWE encryption under a CKKS secret key

Description

The RLWE schemelet of OpenFHE (SchemeletRLWEMP): integers modulo p are encrypted as the coefficients of an RLWE ciphertext over one large modulus q, under the secret key of a CKKS context. It is the input and output format of CKKS functional bootstrapping; see eval_fbt().

Usage

schemelet_get_element_params(private_key, level = 0L)

schemelet_encrypt_coeff(
  input,
  q,
  p,
  private_key,
  element_params,
  bit_reverse = FALSE
)

schemelet_decrypt_coeff(
  input,
  q,
  p,
  private_key,
  element_params,
  num_slots,
  length = 0L,
  bit_reverse = FALSE
)

schemelet_mod_switch(input, q1, q2)

schemelet_get_q_prime(pub_key, lvls)

Arguments

private_key	A PrivateKey of a CKKS context.
level	Integer; number of levels to remove. Default 0L.
input	For schemelet_encrypt_coeff(), a vector of whole numbers, each reduced modulo p as a signed value. For schemelet_decrypt_coeff() and schemelet_mod_switch(), a PolyVector.
q, p, q1, q2	Moduli: strings of decimal digits, or whole numbers of at most 2^53. q is the ciphertext modulus and p the plaintext modulus.
element_params	An ElementParams object from schemelet_get_element_params().
bit_reverse	Logical; encode the input in bit-reversed order (and undo it at decryption). Default FALSE.
num_slots	Integer; the number of slots used in the CKKS computation, which sets the stride between message coefficients.
length	Integer; number of values to return, 0L (default) for num_slots.
pub_key	A PublicKey of a CKKS context.
lvls	Integer; number of moduli after q_0 to include.

Details

schemelet_get_element_params() returns the element parameters of the key's context with level levels removed. Its modulus is the one schemelet_encrypt_coeff() samples its encryption of zero over.

schemelet_encrypt_coeff() encrypts input and returns the RLWE ciphertext modulo q. schemelet_decrypt_coeff() decrypts one, returning values in ⁠(-p/2, p/2]⁠.

schemelet_mod_switch() switches a ciphertext from modulus q2 to modulus q1 in place, scaling by q1/q2 with rounding.

schemelet_get_q_prime() returns the product q_0 * q_1 * ... * q_lvls of the first lvls + 1 RNS moduli of the key's parameters.

Value

schemelet_get_element_params(): an ElementParams object. schemelet_encrypt_coeff(): a PolyVector. schemelet_decrypt_coeff(): a numeric vector. schemelet_mod_switch(): input, invisibly. schemelet_get_q_prime(): a string of decimal digits.

See Also

schemelet_convert_rlwe_to_ckks()

Examples

cc <- fhe_context("CKKS", multiplicative_depth = 2L, scaling_mod_size = 50L,
                  batch_size = 8L)
keys <- key_gen(cc)
ep <- schemelet_get_element_params(keys@secret)
q <- "1152921504606846976"   # 2^60
ct <- schemelet_encrypt_coeff(c(1, 2, 3, 4, 5, 6, 7, 0), q, 16,
                              keys@secret, ep)
schemelet_decrypt_coeff(ct, q, 16, keys@secret, ep, num_slots = 8L)

openfhe.R documentation built on Nov. 13, 2026, 5:07 p.m.