Overview

digest provides `hash' function summaries for GNU R objects. The md5, sha-1 and crc32 hash functions are available. The md5 algorithm by Ron Rivest is specified in RFC 1321, the SHA-1 algorithm is specified in FIPS-180-1 and the crc32 algorithm is described in here. For md5 and sha-1, this packages uses two small standalone C implementations that were provided by by Christophe Devine. For crc32, code from the zlib library is used. Please note that this package is not meant to be used for cryptographic purposes for which more comprehensive (and widely tested) libraries such as OpenSSL should be used.

Example

> library(digest)
> example(digest)

digest> md5Input <- c("", "a", "abc", "message digest", "abcdefghijklmnopqrstuvwxyz",
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
    paste("12345678901234567890123456789012345678901234567890123456789012",
        "34567890123456 ..." ... [TRUNCATED]

digest> md5Output <- c("d41d8cd98f00b204e9800998ecf8427e",
    "0cc175b9c0f1b6a831c399e269772661", "900150983cd24fb0d6963f7d28e17f72",
    "f96b697d7cb7938d525a2f31aaf161d0", "c3fcd3d76192e4007dfb496cca67e13b",
    "d174ab98d277d9f5a5611c2c9f419d9f", "57e ..." ... [TRUNCATED]

digest> for (i in seq(along = md5Input)) {
    md5 <- digest(md5Input[i], serialize = FALSE)
    stopifnot(identical(md5, md5Output[i]))
}

digest> sha1Input <- c("abc", "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
    NULL)

digest> sha1Output <- c("a9993e364706816aba3e25717850c26c9cd0d89d",
    "84983e441c3bd26ebaae4aa1f95129e5e54670f1", "34aa973cd4c4daa4f61eeb2bdbad27316534016f")

digest> for (i in seq(along = sha1Input)) {
    sha1 <- digest(sha1Input[i], algo = "sha1", serialize = FALSE)
    stopifnot(identical(sha1, sha1Output[i]))
}

digest> crc32Input <- c("abc", "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
    NULL)

digest> crc32Output <- c("352441c2", "171a3f5f", "2ef80172")

digest> for (i in seq(along = crc32Input)) {
    crc32 <- digest(crc32Input[i], algo = "crc32", serialize = FALSE)
    stopifnot(identical(crc32, crc32Output[i]))
}

digest> sha1 <- digest("abc", algo = "sha1", serialize = FALSE)

digest> stopifnot(identical(sha1, "a9993e364706816aba3e25717850c26c9cd0d89d"))

digest> digest(list(LETTERS, data.frame(a = letters[1:5],
    b = matrix(1:10, ncol = 2))))
[1] "20f8c37b7860c9d7c4aff15ab254e054"

digest> fname = file.path(R.home(), "COPYING")

digest> x = readChar(fname, file.info(fname)$size)

digest> for (alg in c("sha1", "md5", "crc32")) {
    h1 = digest(x, length = 18000, algo = alg, serialize = FALSE)
    h2 = digest(fname, length = 18000, algo = alg, serialize = FALSE,
        file = TRUE)
    h3 = digest(substr(x, 1, 18000), algo = alg, se .... [TRUNCATED]

digest> library(tools)

digest> fname = file.path(R.home(), "COPYING")

digest> h1 = as.character(md5sum(fname))

digest> h2 = digest(fname, algo = "md5", file = TRUE)

digest> stopifnot(identical(h1, h2))
>

Download

Alternatively, you can also get digest from a Comprehensive R Archive Network (CRAN) node in the src/contrib directory.

Installation

Last modified: Fri Dec 29 20:29:59 CST 2006