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.
Bryan Lewis, who is doing very stuff with websockets and Html5 as he demoed
last week the Chicago R User Group meeting, needed
and was kind enough to send a patch. After some more testing, this change set
is now in the new version which went onto
CRAN earlier today.