Lunatik

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Contents

• Class SKCIPHER
• skcipher

Modules

• completion
• crypto.aead
• crypto.comp
• crypto.rng
• crypto.shash
• crypto.skcipher
• data
• device
• fib
• fifo
• linux
• lunatik
• lunatik.runner
• mailbox
• net
• netfilter
• notifier
• probe
• rcu
• socket
• socket.inet
• syscall
• syscall.table
• thread
• xdp
• xtable

Topics

• README

Module crypto.skcipher

Low-level Lua interface to the Linux Kernel Crypto API for symmetric-key ciphers (SKCIPHER).

This module provides a new function to create SKCIPHER transform objects, which can then be used for encryption and decryption with various block cipher algorithms and modes.

Class SKCIPHER

skcipher

Class SKCIPHER

skcipher:blocksize ()

Gets the block size of the SKCIPHER transform. Data processed by encrypt/decrypt should typically be a multiple of this size, depending on the cipher mode.

Returns:

integer The block size in bytes.

skcipher:decrypt (iv, ciphertext)

Decrypts ciphertext using the SKCIPHER transform. The IV must match the one used during encryption. Ciphertext length should be appropriate for the cipher mode.

Parameters:

• iv string The Initialization Vector. Its length must match ivsize().
• ciphertext string The data to decrypt.

Returns:

string The plaintext.

Raises:

Error on decryption failure, incorrect IV length, or allocation issues.

skcipher:encrypt (iv, plaintext)

Encrypts plaintext using the SKCIPHER transform. The IV (nonce) must be unique for each encryption operation with the same key for most modes. Plaintext length should be appropriate for the cipher mode (e.g., multiple of blocksize).

Parameters:

• iv string The Initialization Vector. Its length must match ivsize().
• plaintext string The data to encrypt.

Returns:

string The ciphertext.

Raises:

Error on encryption failure, incorrect IV length, or allocation issues.

skcipher:ivsize ()

Gets the required initialization vector (IV) size for the SKCIPHER transform.

Returns:

integer The IV size in bytes.

skcipher:setkey (key)

Sets the encryption key for the SKCIPHER transform.

Parameters:

• key string The encryption key.

Raises:

Error if setting the key fails (e.g., invalid key length for the algorithm).

skcipher

new (algname)

Creates a new SKCIPHER transform (TFM) object. This is the constructor function for the crypto_skcipher module.

Parameters:

• algname string The name of the skcipher algorithm (e.g., "cbc(aes)", "ctr(aes)").

Returns:

skcipher The new SKCIPHER TFM object.

Raises:

Error if the TFM object or kernel request cannot be allocated/initialized.

Usage:

local skcipher = require("crypto.skcipher")
local cipher = skcipher.new("cbc(aes)")