You don't have to add 15 pages of checksums: you can also do one checksum per page. It depends on how accurate your OCR or typing skills are.
Here's the thing though. i scanned in a single page of base64 and the original had 3522 characters but the scanned file has more it has 3525. so i can't just go line by line because the lines don't correspond necessarily to the same character positions. so i can't just go by checksums alone. i have extra characters. if the character counts were the same and some characters just got read wrong to a different character then the line by line checksum method might work. but that's not the case.