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.