A new version of the digest package (which generates hash function summaries for arbitrary (and possibly nested) R objects using any of the standard md5, sha-1, sha-256 or crc32 algorithms) is now on CRAN.

Thanks to a patch by Mario Frasca, digest now contains a second (exported) function hmac() to generate Hash-based Message Authentication Code as defined in RFC 2104. Reference output from RFC 2104 is used to validate this functionality as shown below where we run the example code from the hmac() help page:

R> library(digest)
R> example(hmac)

hmacR> ## Standard RFC 2104 test vectors
hmacR> current <- hmac('Jefe', 'what do ya want for nothing?', "md5")

hmacR> target <- '750c783e6ab0b503eaa86e310a5db738'

hmacR> stopifnot(identical(target, as.character(current)))

hmacR> current <- hmac(rep(0x0b, 16), 'Hi There', "md5")

hmacR> target <- '9294727a3638bb1c13f48ef8158bfc9d'

hmacR> stopifnot(identical(target, as.character(current)))

hmacR> current <- hmac(rep(0xaa, 16), rep(0xdd, 50), "md5")

hmacR> target <- '56be34521d144c88dbb8c733f0e8b3f6'

hmacR> stopifnot(identical(target, as.character(current)))

hmacR> ## SHA1 tests inspired to the RFC 2104 and checked against the python
hmacR> ## hmac implementation.
hmacR> current <- hmac('Jefe', 'what do ya want for nothing?', "sha1")

hmacR> target <- 'effcdf6ae5eb2fa2d27416d5f184df9c259a7c79'

hmacR> stopifnot(identical(target, as.character(current)))

hmacR> current <- hmac(rep(0x0b, 16), 'Hi There', "sha1")

hmacR> target <- '675b0b3a1b4ddf4e124872da6c2f632bfed957e9'

hmacR> stopifnot(identical(target, as.character(current)))

hmacR> current <- hmac(rep(0xaa, 16), rep(0xdd, 50), "sha1")

hmacR> target <- 'd730594d167e35d5956fd8003d0db3d3f46dc7bb'

hmacR> stopifnot(identical(target, as.character(current)))
R> 

Also, CRANberries shows the difference to the previsious release 0.4.2 as follows:

Diff between digest versions 0.4.2 dated 2009-12-06 and 0.5.0 dated 2011-05-30

 digest-0.4.2/digest/INDEX                      |only
 digest-0.4.2/digest/R/zzz.R                    |only
 digest-0.4.2/digest/inst                       |only
 digest-0.5.0/digest/ChangeLog                  |only
 digest-0.5.0/digest/DESCRIPTION                |   33 ++++++++++++-------------
 digest-0.5.0/digest/NAMESPACE                  |    7 +++--
 digest-0.5.0/digest/R/hmac.R                   |only
 digest-0.5.0/digest/man/hmac.Rd                |only
 digest-0.5.0/digest/tests/digestTest.Rout.save |    2 -
 digest-0.5.0/digest/tests/hmacTest.R           |only
 digest-0.5.0/digest/tests/hmacTest.Rout.save   |only
 11 files changed, 22 insertions(+), 20 deletions(-)

With that, special thanks to Mario Frasca for the patch and to Henrik Bengtsson for helpful discussion. We took some care to ensure that the existing interface to the digest() function remains unaffected.