Last data update: 2014.03.03
R: compute a hash-based message authentication code
compute a hash-based message authentication code
Description
The hmac
function calculates a message authentication code
(MAC) involving the specified cryptographic hash function in
combination with a given secret key.
Usage
hmac(key, object,
algo = c("md5", "sha1", "crc32", "sha256", "sha512"),
serialize = FALSE, raw = FALSE, ...)
Arguments
key
An arbitrary character or numeric vector, to use as
pre-shared secret key.
object
An arbitrary R object which will then be passed to the
serialize
function, unless the serialize
argument is set to FALSE
.
algo
The algorithms to be used; currently available choices are
md5
, which is also the default, sha1
, crc32
and
sha256
.
serialize
default value of serialize
is here FALSE, not
TRUE as it is in digest
.
raw
This flag alters the type of the output. Setting this to
TRUE
causes the function to return an object of type
"raw"
instead of "character"
.
...
All remaining arguments are passed to digest
.
Value
The hmac
function uses the digest
to return a hash
digest as specified in the RFC 2104.
Author(s)
Mario Frasca mfrasca@zonnet.nl .
References
MD5: http://www.ietf.org/rfc/rfc1321.txt .
SHA-1: http://www.itl.nist.gov/fipspubs/fip180-1.htm .
SHA-256: http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf .
CRC32: The original reference webpage at rocksoft.com
has
vanished from the web; see
https://en.wikipedia.org/wiki/Cyclic_redundancy_check for
general information on CRC algorithms.
http://www.aarongifford.com/computers/sha.html for the
integrated C implementation of sha-512.
The page for the code underlying the C functions used here for sha-1
and md5, and further references, is no longer accessible. Please see
https://en.wikipedia.org/wiki/SHA-1 and
https://en.wikipedia.org/wiki/MD5 .
http://zlib.net for documentation on the zlib library which
supplied the code for crc32.
http://en.wikipedia.org/wiki/SHA_hash_functions for
documentation on the sha functions.
See Also
digest
Examples
## Standard RFC 2104 test vectors
current <- hmac('Jefe', 'what do ya want for nothing?', "md5")
target <- '750c783e6ab0b503eaa86e310a5db738'
stopifnot(identical(target, as.character(current)))
current <- hmac(rep(0x0b, 16), 'Hi There', "md5")
target <- '9294727a3638bb1c13f48ef8158bfc9d'
stopifnot(identical(target, as.character(current)))
current <- hmac(rep(0xaa, 16), rep(0xdd, 50), "md5")
target <- '56be34521d144c88dbb8c733f0e8b3f6'
stopifnot(identical(target, as.character(current)))
## SHA1 tests inspired to the RFC 2104 and checked against the python
## hmac implementation.
current <- hmac('Jefe', 'what do ya want for nothing?', "sha1")
target <- 'effcdf6ae5eb2fa2d27416d5f184df9c259a7c79'
stopifnot(identical(target, as.character(current)))
current <- hmac(rep(0x0b, 16), 'Hi There', "sha1")
target <- '675b0b3a1b4ddf4e124872da6c2f632bfed957e9'
stopifnot(identical(target, as.character(current)))
current <- hmac(rep(0xaa, 16), rep(0xdd, 50), "sha1")
target <- 'd730594d167e35d5956fd8003d0db3d3f46dc7bb'
stopifnot(identical(target, as.character(current)))
Results