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| -rw-r--r-- | haunt/jakob/dynamic/aes.scm | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/haunt/jakob/dynamic/aes.scm b/haunt/jakob/dynamic/aes.scm new file mode 100644 index 0000000..11d4819 --- /dev/null +++ b/haunt/jakob/dynamic/aes.scm @@ -0,0 +1,64 @@ +;;; Copyright © 2019 - 2022 Jakob L. Kreuze <zerodaysfordays@sdf.org> +;;; +;;; This program is free software; you can redistribute it and/or +;;; modify it under the terms of the GNU General Public License as +;;; published by the Free Software Foundation; either version 3 of the +;;; License, or (at your option) any later version. +;;; +;;; This program is distributed in the hope that it will be useful, +;;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +;;; General Public License for more details. +;;; +;;; You should have received a copy of the GNU General Public License +;;; along with this program. If not, see +;;; <http://www.gnu.org/licenses/>. + +(define-module (jakob dynamic aes) + #:use-module (gcrypt random) + #:use-module (system foreign) + #:use-module (rnrs bytevectors) + #:export (new-captcha)) + +(define %libnettle (dynamic-link "libnettle")) +(define %aes256-rounds 14) + +(define %aes-key-size (/ 256 8)) +(define %aes-block-size (/ 128 8)) +(define %tex-aes-key (gen-random-bv %aes-key-size)) + +;; Assume `data' is a bytevector of length `%aes-block-size'. +(define (aes-256-encrypt key data) + (let ((dest (make-bytevector %aes-block-size)) + (%ctx (make-c-struct (map (lambda (_) uint32) (iota (* 4 (+ 1 %aes256-rounds)))) + (map (lambda (_) 0) (iota (* 4 (+ 1 %aes256-rounds)))))) + (%aes-256-encrypt + (pointer->procedure void + (dynamic-func "nettle_aes256_encrypt" %libnettle) + (list '* size_t '* '*))) + (%aes-256-set-encrypt-key + (pointer->procedure void + (dynamic-func "nettle_aes256_set_encrypt_key" %libnettle) + (list '* '*)))) + (%aes-256-set-encrypt-key %ctx (bytevector->pointer %tex-aes-key)) + (%aes-256-encrypt %ctx %aes-block-size (bytevector->pointer dest) (bytevector->pointer data)) + dest)) + +(define (aes-256-decrypt key data) + (let ((dest (make-bytevector %aes-block-size)) + (%ctx (make-c-struct (map (lambda (_) uint32) (iota (* 4 (+ 1 %aes256-rounds)))) + (map (lambda (_) 0) (iota (* 4 (+ 1 %aes256-rounds)))))) + (%aes-256-decrypt + (pointer->procedure void + (dynamic-func "nettle_aes256_decrypt" %libnettle) + (list '* size_t '* '*))) + (%aes-256-set-decrypt-key + (pointer->procedure void + (dynamic-func "nettle_aes256_set_decrypt_key" %libnettle) + (list '* '*)))) + (%aes-256-set-decrypt-key %ctx (bytevector->pointer %tex-aes-key)) + (%aes-256-decrypt %ctx %aes-block-size (bytevector->pointer dest) (bytevector->pointer data)) + dest)) + +;; (utf8->string (aes-256-decrypt %tex-aes-key (aes-256-encrypt %tex-aes-key (string->utf8 "AAAABBBBC hello!")))) +;; => "AAAABBBBC hello!" |