a' = ar mod n  (for odd n),

where n is the modulus, r is the next power of 2 greater than n, and a' is the Montgomery Image we desire. You provide a and n, and CypherCalc chooses r and does the rest. The modulus n is assumed to be loaded into CypherCalc's "N" operand memory.

Here's the procedure:

• Enter the number to be converted into the "Number (a)" box. You can either type this number, drag it from another CypherCalc window, or paste it from another application.
• Click the "Montgomery Image" button. CypherCalc will compute the image and display the result in the "Montgomery Image (a')" box.

The inverse of the Montgomery Image function is the Normal Image function. After a series of Montgomery calculations, you can use CypherCalc to compute the Normal representation of a number from its Montgomery Image.

• Enter the number to be converted into the "Montgomery Image (a')" box. You can either type this number, drag it from another CypherCalc window, or paste it from another application.
• Click the "Normal Image" button. CypherCalc will compute the image and display the result in the "Number (a)" box.