A hard guarantee of privacy that prevents any snapchat message being copied is obviously impossible, but for a lot of people messages which are resistant to casual forwarding by ordinary users is valuable.
The analogy which is usually made with DRM for media is flawed because of the mass audiences for ripped films and music. If one person of the hundreds of thousands who pays for a DRM protected music track cracks the protection off and posts the raw file, the protection is substantially devalued. A snapchat sent to a few people will not be forwarded unless one of the recipients has put forethought into doing so.
All it takes is for one enterprising programmer to write and sell) a snapchat recorder, which would automatically saves all the snapchat photos, while bypassing whatever mechanism snapchat uses to detect picture saving.
In practice, this is actually pretty difficult to do. They can send you cease and desist, block you via the ToS, threaten legal action, add stronger crypto, etc. It's different than DRM because Snapchat owns the entire system.
Also, once your friends realize you're using the "Snapchat recorder" they'll stop sending you snaps entirely.
they read bits from the camera api, transmit them, and draw them on the recipients screen. they don't need to be compatible with any 3rd party like DRM-restricted systems.
The analogy which is usually made with DRM for media is flawed because of the mass audiences for ripped films and music. If one person of the hundreds of thousands who pays for a DRM protected music track cracks the protection off and posts the raw file, the protection is substantially devalued. A snapchat sent to a few people will not be forwarded unless one of the recipients has put forethought into doing so.