Password that associates screen position information with sequentially entered characters

DETAILED DESCRIPTION The present invention associates screen-position information with character information in a password, thereby increasing the password entropy provided by a given number of standard characters, or conversely, decreasing the number of characters needed to reach a given level of password entropy.
Here, standard characters are the characters normally available on keyboards, such as alphanumeric characters and commonly used punctuation.
More particularly, standard characters have a defined binary representation in an accepted standard such as the American National Standard Code for Information Interchange (ASCII), the Extended Binary Coded Decimal Interchange Code (EBCDIC), or the like.
The use of standard characters enables the use of ordinary character-recognition capabilities in the electronic device protected by the inventive password system.
For example, the character recognition mechanism normally provided for other purposes in a miniature electronic device such as a PDA may be used to read password characters entered on a touch screen display, even though these characters may be written freehand with a stylus.
This obviates any need for the special mechanisms for recognizing password images, icons, and the like that are required when visual passwords are used.
According to the invention, the user proffers a password by entering a sequence of standard characters into a screen displayed by the device.
More particularly, FIG.
1 and FIG.
2 show how the screen may be divided into sectors for entering characters and screen-position information.
The structural details of these two figures are, of course, exemplary rather than limiting, and those skilled in the art, once taught the present invention, will appreciate that other ways of organizing the screen may be used as well as those shown.
In FIG.
1, the screen 100 is divided into a character-entry sector 110 and a plurality of position sectors 120.
Each position sector is identified by an ordered pair of integers denoted generally as <i,j>