Second, even if the encryption on your ebooks was perfect and unbreakable, it still would not matter. You cannot protect ink and paper. If someone really wants to post your book on the Internet, they will get a copy of the hardcover, a bandsaw, and a sheet-feeding scanner, and your book will be making its way through the peer-to-peer networks within hours. J.K. Rowling and her publishing companies discovered this for themselves when they adamantly refused to release any Harry Potter ebooks due to piracy concerns, yet complete copies of each Harry Potter book were nonetheless circulating on the Internet within hours of its release.
Division Of Labor bites back!
Get fifty people together to commit to scanning and thoroughly proofing just twenty pages -- or less! -- each in one day and boom, anything in print can be on the Internet.
DRM is dumb. DRM is a pain in the ass for legal purchasers. There hasn't been one DRM effort that has not been defeated. The NSA cries at night over how there are encryption systems out in the wild that worry them.
Any pirate leakage shouldn't be considered lost sales. There are digital packrats who will collect anything with "free" tacked to it. That doesn't mean they will use it or read it!
And for writers, if someone does read a pirate copy, that's mission accomplished: one more reader. Who, if they like the work, will eventually see the wisdom of helping the writer pay his or her rent!
All DRM does is issue a challenge: Go on, try and steal this, I dare you!
All DRM does to legal buyers is add speedbumps to the enjoyment of their purchase. And adds the very real risk of wasting their money down the road, should the DRM method be discontinued.
The end of DRM is coming. Get used to that idea. Embrace that idea now.