Generate a joint automorphism-key share for multi-party rotation — multi_eval_automorphism_key

Produces this party's share of the joined automorphism eval key map for the supplied index_list. Each other party calls the same method with their own secret share, and the shares are combined via multi_add_eval_automorphism_keys() to produce the final joined map.

Usage

multi_eval_automorphism_key_gen(cc, sk, eval_key_map, index_list, key_tag = "")

Arguments

cc: A CryptoContext with the MULTIPARTY feature enabled.
sk: This party's PrivateKey share.
eval_key_map: An existing EvalKeyMap carrying the prior-party automorphism key state, obtained via get_eval_automorphism_key_map() after the lead party has populated the cc registry through key_gen(cc, rotations = ...).
index_list: Integer vector of rotation indices.
key_tag: Character; optional tag to associate with the produced map. Default "".

Value

An EvalKeyMap holding this party's joint share.