Because of all the problems I faced I finally decided to use a third party library - Chilkat
Here is the link: http://www.chilkatsoft.com/crypt-objc.asp On Mon, May 19, 2014 at 10:56 PM, Jens Alfke <j...@mooseyard.com> wrote: > > On May 19, 2014, at 3:06 AM, Devarshi Kulshreshtha > <devarshi.bluec...@gmail.com> wrote: > > 5. Used - wrapSymmetricKey:keyRef: method defined in SecKeyWrapper > class (CryptoExercise example) for encryption, and passed key obtained > from step 3 and data to encrypt obtained from step 4 to it > > > I think you’re misusing wrapSymmetricKey. The NSData you pass into it is not > the message itself; it’s a raw symmetric key. The idea is that you create a > symmetric key at random (probably 32 bytes for an AES-256 key), wrap > (encrypt) that key using the recipient’s public key, encrypt your actual > message using the symmetric key, and then send both the wrapped key and the > encrypted message to the recipient. > > Problem: getting error - too much data for RSA block > > > Yup. RSA can only encrypt a block of the same size as its key, so if you’re > using RSA-2048 the maximum block size is 256 bytes. The padding formats used > with RSA don’t support messages longer than that. In practice, the only > things RSA encrypts are symmetric keys, never messages. > > (If you’re not familiar with concepts like wrapping and padding, you should > really read a good book on cryptography before proceeding. It’s actually > rather dangerous to work on this kind of stuff without a solid understanding > of the principles, because the crypto building blocks can easily be misused > to create systems that are insecure and easily exploited.) > > —Jens -- Thanks, Devarshi _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
