Decrypting an eBook to make it Searchable

So I spent $22 on an ebook for school. It has this crappy DRM that only lets me view the pdf on one computer using only “Adobe Digital Editions”. If that wasn’t so bad, only a small subset of the text is OCR’d, so most of it isn’t even searchable! Now I’m pissed, but wait, what do you say? These files are just RSA encrypted, and I have the key?