share_keys: Distribute a secret key into shares

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

Distribute a secret key into shares

Description

Produces the set of shares that party index would distribute to the other parties under the chosen sharing_scheme. The returned SecretShareMap is opaque; in a real deployment the shares would be serialized and routed over the network to each receiving party, and the receiving parties would store them for use in an abort recovery.

Usage

share_keys(cc, sk, n_parties, threshold, index, sharing_scheme = "additive")

Arguments

cc	A CryptoContext with the MULTIPARTY feature.
sk	The PrivateKey to share.
n_parties	Integer; total number of parties.
threshold	Integer; minimum number of shares needed to reconstruct. For "additive" this must be n_parties - 1; for "shamir" it is typically floor(n_parties/2) + 1.
index	Integer; the 1-based index of the party owning sk (the "my share index").
sharing_scheme	Character; either "additive" (default) or "shamir".

Details

Two sharing schemes are supported:

• "additive" — N-1 threshold; every party must contribute their share to reconstruct. Robust against corruption of any single party's storage but not against any party dropping out.

• "shamir" — floor(N/2) + 1 threshold; the secret can be reconstructed from any majority subset of the distributed shares. Robust against up to floor((N-1)/2) parties dropping out.

Value

A SecretShareMap suitable for passing to recover_shared_key(). length() of it is the number of shares.

See Also

recover_shared_key()

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