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

BFVParams

R Documentation

BFV Parameters

Description

Constructor for the BFV scheme's CCParams surface. Every argument maps 1:1 to an upstream ⁠CCParams<CryptoContextBFVRNS>::Set*⁠ method whose override is not disabled in the BFV specialization. The 13 setters that BFV explicitly disables (SetScalingTechnique, SetFirstModSize, SetPRENumHops, SetExecutionMode, …) are not exposed here.

Usage

BFVParams(
  plaintext_modulus = NULL,
  multiplicative_depth = NULL,
  scaling_mod_size = NULL,
  batch_size = NULL,
  security_level = NULL,
  secret_key_dist = NULL,
  key_switch_technique = NULL,
  ring_dim = NULL,
  digit_size = NULL,
  num_large_digits = NULL,
  standard_deviation = NULL,
  multiparty_mode = NULL,
  threshold_num_of_parties = NULL,
  multiplication_technique = NULL,
  max_relin_sk_deg = NULL,
  pre_mode = NULL,
  eval_add_count = NULL,
  key_switch_count = NULL,
  encryption_technique = NULL
)

Arguments

`plaintext_modulus`	Integer modulus `t` for the BFV plaintext space. BFV plaintexts are elements of `Z_t[x]/Phi_m(x)` and every homomorphic operation is performed modulo `t`. Must be a prime (or a composite supporting NTT in the batching case) and must be at least large enough that the end-to-end computation does not wrap modulo `t`. Typical values: `65537` (the smallest batching-friendly prime) for small-integer arithmetic, `786433` or larger when the operands or intermediate sums are larger. There is no scheme-level default — the user must supply one.
`multiplicative_depth`	Integer depth of the multiplication circuit the context must support. BFV and BGV grow ciphertext noise with each multiplication, and the ring modulus `q` is sized by OpenFHE to survive exactly `multiplicative_depth` successive multiplications plus an `EvalAdd` chain between them. Set to the exact depth of your circuit; setting it too small causes correctness failure at decrypt, setting it too large inflates ring dimension and slows every operation. Couples tightly to `security_level` (together they pin `ring_dim`).
`scaling_mod_size`	Integer bit-size of each intermediate scaling modulus in the RNS decomposition of `q`. Default leaves OpenFHE to choose from its internal tables (typically 60 bits). Override only when you know your depth budget needs a tighter value; the upstream simple-integers example uses the default.
`batch_size`	Integer number of SIMD-batched plaintext slots. Default is `ring_dim / 2` under the full-packing convention. Set to a smaller power of two when your input vector is short and rotation cost dominates the circuit (the inner-product idiom). Must divide `ring_dim / 2`. Couples to `ring_dim`.
`security_level`	One of `SecurityLevel$HEStd_128_classic` (default when unset), `HEStd_192_classic`, `HEStd_256_classic`, and their `⁠_quantum⁠` counterparts. Fixes the target hardness assumption and, together with `multiplicative_depth`, determines the minimum ring dimension via the upstream lattice-parameters tables in `core/lattice/stdlatticeparms.h`.
`secret_key_dist`	One of `SecretKeyDist$GAUSSIAN`, `UNIFORM_TERNARY` (default under classic lattice parameters), or `SPARSE_TERNARY`. Controls the coefficient distribution of the secret key. Change only for research scenarios that demand a specific distribution; every production vignette uses the default.
`key_switch_technique`	One of `KeySwitchTechnique$BV` (default for BFV) or `HYBRID`. `BV` produces smaller evaluation keys and is the simpler option; `HYBRID` is relevant only when you are also setting `num_large_digits` and benchmarking rotation cost.
`ring_dim`	Integer power-of-two lattice ring dimension. Default (`NULL`) asks OpenFHE to compute the minimum ring dimension that satisfies `security_level` at the chosen `multiplicative_depth`. Override only to force a larger value than the auto-selection, typically to reserve headroom for later parameter sweeps.
`digit_size`	Integer `r` for BV key-switching: the base-`2^r` digit decomposition of the ciphertext during a key-switch. Default `0L` selects the upstream default. Larger values decrease the number of digit multiplications at the cost of larger per-digit noise.
`num_large_digits`	Integer number of digit groupings in HYBRID key switching. Only meaningful when `key_switch_technique = KeySwitchTechnique$HYBRID`; ignored otherwise. Default `0L` lets OpenFHE pick.
`standard_deviation`	Numeric standard deviation of the Gaussian error distribution used during key generation and encryption. Default (`NULL`) uses the upstream default `3.19`. Override only in research scenarios.
`multiparty_mode`	One of `MultipartyMode$FIXED_NOISE_MULTIPARTY` or `NOISE_FLOODING_MULTIPARTY`. Selects between threshold-FHE with fixed noise (no flooding) and noise-flooding-protected threshold-FHE. Both cox-threshold and CVXR-consensus-ADMM vignettes rely on threshold paths; leave at upstream default unless you are intentionally tuning the leakage/performance trade-off.
`threshold_num_of_parties`	Integer count of parties in an n-of-n threshold protocol. Ignored in non-threshold contexts. The cox-threshold vignette uses 2; the threshold-fhe-5p Python example uses 5.
`multiplication_technique`	One of `MultiplicationTechnique$BEHZ`, `HPS`, `HPSPOVERQ`, `HPSPOVERQLEVELED`. BFV-specific choice of how the plaintext modulus interacts with the ciphertext modulus during multiply. Default upstream is `HPSPOVERQLEVELED`; override only if you are benchmarking multiplication-path variants.
`max_relin_sk_deg`	maximum degree of the secret key that can be relinearized. Upstream default is 2. No current vignette or Python example exercises this; the cpp11 binding is in place so a later release can promote it without a recompile.
`pre_mode`	proxy re-encryption mode (`PREMode$NOT_SET`, `INDCPA`, `FIXED_NOISE_HRA`, `NOISE_FLOODING_HRA`). Only meaningful if the `PRE` feature is enabled on the context. No current vignette uses PRE.
`eval_add_count`	upstream noise-budget hint: maximum additions between multiplications. Used only by the noise-flooding path. Default 0.
`key_switch_count`	upstream noise-budget hint: maximum key-switch count. Default 0.
`encryption_technique`	BFV-specific encryption variant (`EncryptionTechnique$STANDARD` or `EXTENDED`). Default STANDARD.