I believe US patent 8,625,805, granted to Wickr on January 7, 2014, is either not novel, or an obvious variation of ordinary encrypted mail as it has been used for decades. Here is claim 1:
- A system, comprising: a processor configured to: request a public key and a device identifier of at least one recipient from a first server; encrypt a message containing one or more components using a symmetric key; encrypt the symmetric key with a public key received in response to the request; encapsulate the encrypted message, the encrypted symmetric key, and the device identifier in a digital security bubble encapsulation; and transmit the digital security bubble encapsulation to a second server; and a memory coupled to the processor and configured to provide the processor with instructions.
The "digital security bubble" is a fanciful name for the well known concept of a "digital envelope". See, for example, IETF RFC 5652, Cryptographic Message Syntax, Section 6. The only thing unusual in the claim is the use of a device identifier instead of a user identifier. However nothing prevents ordinary encrypted mail from being addressed to a device instead of a user, in which case the certificate of the recipient comprises a public key and a device identifier. In all likelihood ordinary encrypted mail was addressed to devices before the patent application was filed, in which case what is claimed is not novel. But even if that were not the case, addressing a message to a device instead of a user would be a trivial variation on the prior art.
What could be done to challenge this patent? I've looked at the Post Grant Review process, but it's extraordinarily complex and expensive.
Update: Following the advice in the answer given by Phoenix88, I studied the patent in detail, and I filed a submission of prior art under 37 CFR 1.501 and 35 USC 301. As I was studying the patent, I realized that there were other issues besides prior art; in particular, claim 16 illustrates a problem specific to security claims that I don't think has been discussed before. Also, after being told by George White in his comment that US 8,625,805 was a Track I case, I also filed a response to the current USPTO call for comments on crowdsourcing of prior art pointing out loopholes that prevent third party scrutiny of applications. I have written a blog post about all this, since it would be off-topic to discuss it here.