;;; hashcash.el --- Add hashcash payments to email
-;; $Revision: 1.3 $
+;; $Revision: 1.4 $
;; Copyright (C) 1997,2001 Paul E. Foley
;; Maintainer: Paul Foley <mycroft@actrix.gen.nz>
See `hashcash-payment-alist'."
:type 'integer)
-(defcustom hashcash-payment-alist nil
+(defcustom hashcash-payment-alist '()
"*An association list mapping email addresses to payment amounts.
Elements may consist of (ADDR AMOUNT) or (ADDR STRING AMOUNT), where
ADDR is the email address of the intended recipient and AMOUNT is
the value of hashcash payment to be made to that user. STRING, if
present, is the string to be hashed; if not present ADDR will be used.")
+(defcustom hashcash-default-accept-payment 10
+ "*The default minimum number of bits to accept on incoming payments."
+ :type 'integer)
+
+(defcustom hashcash-accept-resources `((,(user-mail-address) nil))
+ "*An association list mapping hashcash resources to payment amounts.
+Resources named here are to be accepted in incoming payments. If the
+corresponding AMOUNT is NIL, the value of `hashcash-default-accept-payment'
+is used instead.")
+
(defcustom hashcash "/usr/local/bin/hashcash"
"*The path to the hashcash binary.")
+(defcustom hashcash-double-spend-database "hashcash.db"
+ "*The path to the double-spending database.")
+
(defcustom hashcash-in-news nil
"*Specifies whether or not hashcash payments should be made to newsgroups."
:type 'boolean)
(buffer-substring (point-at-bol) (point-at-eol)))
nil))
+(defun hashcash-check-payment (token str val)
+ "Check the validity of a hashcash payment."
+ (zerop (call-process hashcash nil nil nil "-c"
+ "-d" "-f" hashcash-double-spend-database
+ "-b" (number-to-string val)
+ "-r" str
+ token)))
+
+;;;###autoload
(defun hashcash-insert-payment (arg)
- "Insert an X-Hashcash header with a payment for ARG"
+ "Insert X-Payment and X-Hashcash headers with a payment for ARG"
(interactive "sPay to: ")
(let ((pay (hashcash-generate-payment (hashcash-payment-to arg)
(hashcash-payment-required arg))))
(when pay
+ (insert-before-markers "X-Payment: hashcash 1.1 " pay "\n")
(insert-before-markers "X-Hashcash: " pay "\n"))))
+;;;###autoload
+(defun hashcash-verify-payment (token &optional resource amount)
+ "Verify a hashcash payment"
+ (let ((key (cadr (split-string-by-char token ?:))))
+ (cond ((null resource)
+ (let ((elt (assoc key hashcash-accept-resources)))
+ (and elt (hashcash-check-payment token (car elt)
+ (or (cadr elt) hashcash-default-accept-payment)))))
+ ((equal token key)
+ (hashcash-check-payment token resource
+ (or amount hashcash-default-accept-payment)))
+ (t nil))))
+
;;;###autoload
(defun mail-add-payment (&optional arg)
- "Add an X-Hashcash: header with a hashcash payment for each recipient address
-Prefix arg sets default payment temporarily."
+ "Add X-Payment: and X-Hashcash: headers with a hashcash payment
+for each recipient address. Prefix arg sets default payment temporarily."
(interactive "P")
(let ((hashcash-default-payment (if arg (prefix-numeric-value arg)
hashcash-default-payment))
(mapc #'hashcash-insert-payment addrlist)))))
t)
+;;;###autoload
+(defun mail-check-payment (&optional arg)
+ "Look for a valid X-Payment: or X-Hashcash: header.
+Prefix arg sets default accept amount temporarily."
+ (interactive "P")
+ (let ((hashcash-default-accept-payment (if arg (prefix-numeric-value arg)
+ hashcash-default-accept-payment)))
+ (save-excursion
+ (goto-char (point-min))
+ (search-forward mail-header-separator)
+ (beginning-of-line)
+ (let ((end (point))
+ (ok nil))
+ (goto-char (point-min))
+ (while (and (not ok) (search-forward "X-Payment: hashcash 1.1 " end t))
+ (setq ok (hashcash-verify-payment
+ (buffer-substring (point) (point-at-eol)))))
+ (goto-char (point-min))
+ (while (and (not ok) (search-forward "X-Hashcash: " end t))
+ (setq ok (hashcash-verify-payment
+ (buffer-substring (point) (point-at-eol)))))
+ (when ok
+ (message "Payment valid"))
+ ok))))
+
(provide 'hashcash)
;;; hashcash.el ends here