add random password/username generation

1 files changed, 44 insertions, 11 deletions

diff --git a/kasi.el b/kasi.el
index f2ca588..1031afd 100644
--- a/kasi.el
+++ b/kasi.el
@@ -44,35 +44,68 @@
 
 (defvar kasi-version "1.0")
 
-(defun kasi-filename-short (file)
+(defun kasi--filename-short (file)
   "Returns shortened name of filename."
   (file-name-sans-extension
    (file-relative-name file kasi-dir)))
 
-(defun kasi-filename ()
+(defun kasi--filename ()
   "Returns full filename of the secret file."
   (let* ((filenames (file-expand-wildcards (format "%s/*/*" kasi-dir)))
          (options (mapcar (lambda (f)
-                            (kasi-filename-short f))
+                            (kasi--filename-short f))
                           filenames))
          (selected (completing-read "File: " options))
          (file (elt filenames (seq-position options selected))))
     file))
 
-(defun kasi-get (file elem)
+(defun kasi--get (file elem)
   "Returns element from secret file."
   (car (with-temp-buffer
          (insert-file-contents file)
          (alist-get elem (read (current-buffer))))))
 
-(defun kasi-totp (file)
+(defun kasi--totp (file)
   "Returns current TOTP code from secret file."
-  (let* ((totp-secret (kasi-get file 'totp))
+  (let* ((totp-secret (kasi--get file 'totp))
          (totp-code (totp (base32-hex-decode totp-secret))))
     (kill-new totp-code)
     (message (format "TOTP %s for %s copied to kill ring"
                      totp-code
-                     (kasi-filename-short file)))))
+                     (kasi--filename-short file)))))
+
+(defun kasi--random-string (length charset)
+   "Generate a random string of LENGTH using characters from CHARSET.
+Uses /dev/urandom for cryptographic security."
+   ;; I have not seen any other built-in way to get cryptographically
+   ;; random outputs in Emacs.
+   (let* ((bytes (with-temp-buffer
+                   (call-process "dd" nil (current-buffer) nil
+                                 "if=/dev/urandom" "bs=1" (format "count=%d" (* length 4)))
+                   (buffer-string)))
+          (charset-len (length charset))
+          (result ""))
+     (dotimes (i length)
+       (setq result (concat result
+                            (char-to-string
+                             (aref charset
+                                   (% (aref bytes i)
+                                      charset-len))))))
+     result))
+
+;;;###autoload
+(defun kasi-generate-password (&optional length)
+  "Generate a random password of LENGTH (default 32)."
+  (interactive "P")
+  (let ((charset "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\"!#$%&'()*+,-./:;<=>?@[]^_`{|}~"))
+    (message (kasi--random-string (or length 32) charset))))
+
+;;;###autoload
+(defun kasi-generate-username (&optional length)
+  "Generate a random username of LENGTH (default 12)."
+  (interactive "P")
+  (let ((charset "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"))
+    (message (kasi--random-string (or length 12) charset))))
 
 ;;;###autoload
 (defun kasi (command file)
@@ -83,15 +116,15 @@
                                                 username
                                                 email
                                                 totp)))
-                     (kasi-filename)))
+                     (kasi--filename)))
   (pcase command
     ('edit (find-file-other-window file))
-    ('totp (kasi-totp file))
+    ('totp (kasi--totp file))
     ((or 'password 'username 'email)
      (progn
-       (kill-new (kasi-get file command))
+       (kill-new (kasi--get file command))
        (message (format "Copied %s for %s to kill ring."
                         command
-                        (kasi-filename-short file)))))))
+                        (kasi--filename-short file)))))))
 
 (provide 'kasi)