decrypt: Decrypt a ciphertext

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

Decrypt a ciphertext

Description

decrypt dispatches on both arguments and accepts them in either order, as the C++ header does: Decrypt(ciphertext, privateKey) is the primary form and Decrypt(privateKey, ciphertext) forwards to it (cryptocontext.h, both overloads). The key-first order lets code that is written around the holder of the key, such as a party object in a protocol, put that holder first, the same way encrypt() puts the key first.

Usage

decrypt(ct, key, ...)

Arguments

ct	A Ciphertext, or a PrivateKey when the key-first order is used.
key	A PrivateKey, or a Ciphertext when the key-first order is used.
...	Additional arguments (cc = CryptoContext)

Value

A Plaintext

Examples

cc <- fhe_context("CKKS", multiplicative_depth = 2L,
                  scaling_mod_size = 50L, batch_size = 8L)
kp <- key_gen(cc, eval_mult = TRUE)
pt <- make_ckks_packed_plaintext(cc, c(0.25, 0.5, 0.75, 1))
ct <- encrypt(kp@public, pt, cc = cc)

## Add the encrypted vector to itself, then decrypt. Decryption
## returns a Plaintext padded out to the full slot count, so trim it
## back to the length that was encoded.
out <- decrypt(eval_add(ct, ct), kp@secret, cc = cc)
out <- set_length(out, 4L)
get_real_packed_value(out)

## The same call with the key first:
out2 <- decrypt(kp@secret, eval_add(ct, ct), cc = cc)
get_real_packed_value(set_length(out2, 4L))

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