FunctionPackage: exclToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 9.0
Moderately revised from 8.2.
8.2 version


Arguments: context &key return

Finalize and return the SHA224 hash from context in a format determined by the return keyword argument.

return can be one of the following values:

cl-user(4): (setq c (sha224-init))
#S(excl::md-context :ctx 9183104 :size 28)
cl-user(5): (sha224-update c "foo")
cl-user(6): (sha224-final c :return :usb8)
#(8 8 246 78 96 213 137 121 252 182 ...)

;;  Potential problem with :return :integer (or :return unspecified
;;  as the default is :integer). The call is to SHA224-FILE which calls
;;  SHA224-FINAL and returns the value SHA224-FINAL returns.
;;  Here we get the sha224 value in a shell:
% openssl dgst -sha224 -hex uninstall.jpg 
SHA224(uninstall.jpg)= 012d03e402813fa87201182a9fa8dc71d5662e07a3298e6e3fee902a

;; Now we get it with SHA224-FILE:
cl-user(17): (sha224-file "~/uninstall.jpg")
cl-user(18): (format t "~x" *)

;; Note the hex values are the same but the leading 0 is not printed
;; by Lisp, which is dealing with the value as an integer. The leading
;; 0 is preserved when the :return is :hex:
cl-user(21): (sha224-file "~/unistall.jpg" :return :hex)

See MD*, SHA*, HMAC, and other message digest support in miscellaneous.htm. See also digest-final.

Copyright (c) 1998-2017, Franz Inc. Oakland, CA., USA. All rights reserved.
This page has had moderate revisions compared to the 8.2 page.
Created 2017.2.15.

Allegro CL version 9.0
Moderately revised from 8.2.
8.2 version