Copyright	(c) Leo D 2023
License	BSD-3-Clause
Maintainer	leo@apotheca.io
Stability	experimental
Portability	POSIX
Safe Haskell	Safe-Inferred
Language	Haskell2010

Botan.Bindings.ZFEC

Description

The ZFEC module provides forward error correction compatible with the zfec library.

Forward error correction takes an input and creates multiple “shares”, such that any K of N shares is sufficient to recover the entire original input.

Note

Specific to the ZFEC format, the first K generated shares are identical to the original input data, followed by N-K shares of error correcting code. This is very different from threshold secret sharing, where having fewer than K shares gives no information about the original input.

Warning

If a corrupted share is provided to the decoding algorithm, the resulting decoding will be invalid. It is recommended to protect shares using a technique such as a MAC or public key signature, if corruption is likely in your application.

ZFEC requires that the input length be exactly divisible by K; if needed define a padding scheme to pad your input to the necessary size.

Synopsis

botan_zfec_encode :: CSize -> CSize -> ConstPtr Word8 -> CSize -> Ptr (Ptr Word8) -> IO CInt
botan_zfec_decode :: CSize -> CSize -> ConstPtr CSize -> ConstPtr (ConstPtr Word8) -> CSize -> Ptr (Ptr Word8) -> IO CInt

Documentation

botan_zfec_encode Source #

Arguments

:: CSize	K: the number of shares needed for recovery
-> CSize	N: the number of shares generated
-> ConstPtr Word8	input: the data to FEC
-> CSize	size: the length in bytes of input, which must be a multiple of K
-> Ptr (Ptr Word8)	outputs: An out parameter pointing to a fully allocated array of size [N][size / K]. For all n in range, an encoded block will be written to the memory starting at outputs[n][0].
-> IO CInt	0 on success, negative on failure

Encode some bytes with certain ZFEC parameters.

botan_zfec_decode Source #

Arguments

:: CSize	K: the number of shares needed for recovery
-> CSize	N: the total number of shares
-> ConstPtr CSize	indexes: The index into the encoder's outputs for the corresponding element of the inputs array. Must be of length K.
-> ConstPtr (ConstPtr Word8)	inputs: K previously encoded shares to decode
-> CSize	shareSize: the length in bytes of each input
-> Ptr (Ptr Word8)	outputs: An out parameter pointing to a fully allocated array of size [K][shareSize]. For all k in range, a decoded block will written to the memory starting at outputs[k][0].
-> IO CInt	0 on success, negative on failure

Decode some previously encoded shares using certain ZFEC parameters.