make_chebyshev_basis

Engine.make_chebyshev_basis(ciphertext, max_power, relineraization_key)

Make a Chebyshev basis, which is \([T_1(x), T_2(x), \dots, T_{max\_power}(x)]\) for the given ciphertext \(x\), where \(T_n(x)\) is the \(n\)th Chebyshev polynomial.

• Input:
  • Ciphertext
  • max_power: the maximum power of the power basis
  • RelinearizationKey
• Output:
  • chebyshev_basis: an array of Ciphertexts

from liberate import Engine

engine = Engine()
secret_key = engine.create_secret_key()
public_key = engine.create_public_key(secret_key)
relinearization_key = engine.create_relinearization_key(secret_key)

message = [1, 2, 3]
ciphertext = engine.encrypt(message, public_key)

chebyshev_basis = engine.make_chebyshev_basis(
    ciphertext, max_power=3, relinearization_key
)