+ sign))
+ (pop-to-buffer pgg-errors-buffer)
+ (error "Encrypt error"))
+ (delete-region (point-min) (point-max))
+ (insert "\n")
+ (insert-buffer-substring pgg-output-buffer)
+ t)
+
+;; epg wrapper
+
+(defvar epg-user-id-alist)
+
+(autoload 'epg-make-context "epg")
+(autoload 'epg-passphrase-callback-function "epg")
+(autoload 'epa-select-keys "epa")
+(autoload 'epg-list-keys "epg")
+(autoload 'epg-context-set-armor "epg")
+(autoload 'epg-context-set-textmode "epg")
+(autoload 'epg-context-set-signers "epg")
+(autoload 'epg-context-set-passphrase-callback "epg")
+(autoload 'epg-key-sub-key-list "epg")
+(autoload 'epg-sub-key-capability "epg")
+(autoload 'epg-sub-key-validity "epg")
+(autoload 'epg-sub-key-fingerprint "epg")
+(autoload 'epg-sign-string "epg")
+(autoload 'epg-encrypt-string "epg")
+(autoload 'epg-configuration "epg-config")
+(autoload 'epg-expand-group "epg-config")
+
+(defvar mml1991-epg-secret-key-id-list nil)
+
+(defun mml1991-epg-passphrase-callback (context key-id ignore)
+ (if (eq key-id 'SYM)
+ (epg-passphrase-callback-function context key-id nil)
+ (let* ((entry (assoc key-id epg-user-id-alist))
+ (passphrase
+ (password-read
+ (format "GnuPG passphrase for %s: "
+ (if entry
+ (cdr entry)
+ key-id))
+ (if (eq key-id 'PIN)
+ "PIN"
+ key-id))))
+ (when passphrase
+ (let ((password-cache-expiry mml1991-passphrase-cache-expiry))
+ (password-cache-add key-id passphrase))
+ (setq mml1991-epg-secret-key-id-list
+ (cons key-id mml1991-epg-secret-key-id-list))
+ (copy-sequence passphrase)))))
+
+(defun mml1991-epg-find-usable-key (keys usage)
+ (catch 'found
+ (while keys
+ (let ((pointer (epg-key-sub-key-list (car keys))))
+ ;; The primary key will be marked as disabled, when the entire
+ ;; key is disabled (see 12 Field, Format of colon listings, in
+ ;; gnupg/doc/DETAILS)
+ (unless (memq 'disabled (epg-sub-key-capability (car pointer)))
+ (while pointer
+ (if (and (memq usage (epg-sub-key-capability (car pointer)))
+ (not (memq (epg-sub-key-validity (car pointer))
+ '(revoked expired))))
+ (throw 'found (car keys)))
+ (setq pointer (cdr pointer)))))
+ (setq keys (cdr keys)))))
+
+;; XXX: since gpg --list-secret-keys does not return validity of each
+;; key, `mml1991-epg-find-usable-key' defined above is not enough for
+;; secret keys. The function `mml1991-epg-find-usable-secret-key'
+;; below looks at appropriate public keys to check usability.
+(defun mml1991-epg-find-usable-secret-key (context name usage)
+ (let ((secret-keys (epg-list-keys context name t))
+ secret-key)
+ (while (and (not secret-key) secret-keys)
+ (if (mml1991-epg-find-usable-key
+ (epg-list-keys context (epg-sub-key-fingerprint
+ (car (epg-key-sub-key-list
+ (car secret-keys)))))
+ usage)
+ (setq secret-key (car secret-keys)
+ secret-keys nil)
+ (setq secret-keys (cdr secret-keys))))
+ secret-key))
+
+(defun mml1991-epg-sign (cont)
+ (let ((context (epg-make-context))
+ headers cte signer-key signers signature)
+ (if (eq mm-sign-option 'guided)
+ (setq signers (epa-select-keys context "Select keys for signing.
+If no one is selected, default secret key is used. "
+ mml1991-signers t))
+ (if mml1991-signers
+ (setq signers (delq nil
+ (mapcar
+ (lambda (name)
+ (setq signer-key
+ (mml1991-epg-find-usable-secret-key
+ context name 'sign))
+ (unless (or signer-key
+ (y-or-n-p
+ (format
+ "No secret key for %s; skip it? "
+ name)))
+ (error "No secret key for %s" name))
+ signer-key)
+ mml1991-signers)))))
+ (epg-context-set-armor context t)
+ (epg-context-set-textmode context t)
+ (epg-context-set-signers context signers)
+ (if mml1991-cache-passphrase
+ (epg-context-set-passphrase-callback
+ context
+ #'mml1991-epg-passphrase-callback))
+ ;; Don't sign headers.
+ (goto-char (point-min))
+ (when (re-search-forward "^$" nil t)
+ (setq headers (buffer-substring (point-min) (point)))
+ (save-restriction
+ (narrow-to-region (point-min) (point))
+ (setq cte (mail-fetch-field "content-transfer-encoding")))
+ (forward-line 1)
+ (delete-region (point-min) (point))
+ (when cte
+ (setq cte (intern (downcase cte)))
+ (mm-decode-content-transfer-encoding cte)))
+ (condition-case error
+ (setq signature (epg-sign-string context (buffer-string) 'clear)
+ mml1991-epg-secret-key-id-list nil)
+ (error
+ (while mml1991-epg-secret-key-id-list
+ (password-cache-remove (car mml1991-epg-secret-key-id-list))
+ (setq mml1991-epg-secret-key-id-list
+ (cdr mml1991-epg-secret-key-id-list)))
+ (signal (car error) (cdr error))))