;;; in addition to sha1, ironclad provides sha224, sha256, sha384, and sha512.
(defun sha1-hash (data)
  (let ((sha1 (ironclad:make-digest 'ironclad:sha1))
        (bin-data (ironclad:ascii-string-to-byte-array data)))
    (ironclad:update-digest sha1 bin-data)
    (ironclad:byte-array-to-hex-string (ironclad:produce-digest sha1))))