• Signature Verification: A good forger can reproduce the appearance of a signature, but reproducing its dynamic sequence is more difficult.

• Direct computer input of pictographic characters, as in the Chinese, Japanese, and Korean languages.

• Pen-input computing systems that rely on writing, or a pen, as the sole or major input.

Crane's early work culminated in a first publication in 1960 and a first patent in 1964 for a special pen device. These initial efforts took a more advanced form in the early 1970s with a system that used what is now generally referred to as the "SRI pen" as a method of inputting characters into a computer. This method was described in a journal article published in 1977. A basic method for inputting handwritten Chinese characters was published later in the same year. The first patent in the area of signature verification was issued in 1974. In 1991, a patent was issued for a version of the pen that takes dynamic information in five dimensions.

In late 1981, Communication Intelligence Corporation (CIC) was formed to develop and commercialize SRI's pen-input technology. Early CIC products included the pen-input notebook computer from NCR Corporation, the MacHandwriter (a CIC product based on Japanese writing distributed by Apple Computer in Japan), and the PenDOS software that allows existing DOS applications to use pen input. The work done on the SRI pen led to the original system for direct computer input of Chinese characters that was commercialized by CIC. The advanced software developed by John Ostrem (formerly of SRI and later of CIC) is used by CIC's on-line signature verification system.