Document reg code accepted on iSilo for iPhone but not in iSilo for Mac OS X
A user of one of my documents reports that the same document opens with the document registration code on iSilo for iPhone but he gets an invalid registration code message when trying to open it on iSilo for Mac OS X.
Version 5.19 added a feature to help determine which part of a document registration code is entered incorrectly. When a user enters an asterisk '*' as the first character before the registration code and the registration code is incorrect, iSilo displays an additional line for troubleshooting with the form R123456 U1234 D1234 P123456. For basic troubleshooting purposes, we just need to pay attention to the first four digits after the R. Each digit after the R represents a checksum on four characters of the registration code.
An example will help demonstrate how to use this feature.
Note that since only a single digit is used as a checksum for four characters whose individual values may be any digit of letter, that it is possible for the troubleshooting checksum digits to agree even if the user enters the wrong registration code. If this happens, then the next step may be to ask the user to take a picture of the screen with the registration code entered so that you can verify visually yourself what the user has entered.
- Let us say that the correct registration code is A1B2-C3D4-E5F6-G7H8.
- Using iSilo, open a sample document that requires a registration code for which the registration code in #1 is incorrect and enter that registration code preceded by an asterisk: *A1B2-C3D4-E5F6-G7H8
- iSilo reports that the registration code is incorrect and shows the troubleshooting line. That line should begin with R2688. Ignore everything after those first four digits after the R. Try this yourself. From this, we know that if the user entered every one of the 16 characters of the registration code correctly, then the four digits after the R should be 2688. The first digit '2' is a checksum on the first four set of characters 'A1B2'. The second digit '6' is a checksum on the second set of four characters 'C3D4'. The third digit '8' is a checksum on the third set of four characters 'E5F6'. The fourth digit '8' is a checksum on the third set of four characters 'G7H8'.
- So given the checksum digits we have from step #3, we ask the user to add an asterisk before the first character. Let us say that the user is incorrectly seeing the 3 in the second set of four characters as the letter E, so the user enters: *A1B2-CED4-E5F6-G7H8. iSilo will report a troubleshooting line that begins with R2088. Notice that R2088 differs from the R2688 result that we got in #3 in that the second digit is different between the two, meaning that there is definitely something wrong with what the user entered in the second set of four characters.