Dirk Eddelbuettel <edd@debian.org> with contributions 
 by Antoine Lucas, Jarek Tuszynski, Henrik Bengtsson, Simon Urbanek,
 Mario Frasca, Bryan Lewis, Murray Stokely, Hannes Muehleisen,
 Duncan Murdoch, Jim Hester and Wush Wu.
Create Cryptographic Hash Digests of R Objects
Implementation of a function 'digest()' for the creation 
 of hash digests of arbitrary R objects (using the md5, sha-1, sha-256, 
 crc32, xxhash and murmurhash algorithms) permitting easy comparison of R
 language objects, as well as a function 'hmac()' to create hash-based
 message authentication code.

   The md5 algorithm by Ron Rivest is specified in RFC 1321, the sha-1 
 and sha-256 algorithms are specified in FIPS-180-1 and FIPS-180-2, 
 and the crc32 algorithm is described in 
 ftp://ftp.rocksoft.com/cliens/rocksoft/papers/crc_v3.txt.

   For md5, sha-1, sha-256 and aes, this package uses small standalone
 implementations that were provided by Christophe Devine. For crc32, code
 from the zlib library is used. For sha-512, an implementation by Aaron
 D. Gifford is used. For xxHash, the implementation by Yann Collet is used.
 For murmurhash, an implementation by Shane Day is used.

   Please note that this package is not meant to be deployed for 
 cryptographic purposes for which more comprehensive (and widely 
 tested) libraries such as OpenSSL should be used.