Secfone beyond encrypted mobile communication - Key protection

A recent blog post on the impacts of Snowden's leaded documents on encryption softwares skyrocketed on this blog. Thanks folks!

However several questions came up concerning Secfone's solution let me answer them here. I try not to be too technical, so it will be understandable for non-infosec users too.

How Secfone protects encryption keys?

One of the fundamental issues in communication encryption is how the solution protects the encryption keys. If the keys are compromised, than the communication can easily be tapped. Encryption softwares can use only the device's (smartphone) store and CPU to store, generate, manage and use encryption keys. However these hardware elements are not designed to protect anything. This is one of the biggest weak-point of all encryption software.

Secfone uses TPM technology (Trusted Platform Module), a cryptochip integrated into a micro SD card (the card goes into the micro SD slot of the smartphone). This hardware piece is designed to generate, store, manage, use and PROTECT encryption keys. The cryptochip is designed to be very sensitive on purpose. That means the information can't be retrieved from the chip (it is not readable by design). If you try to hack the cryptochip - with an oscilloscope, or put it under an electro-microscope, try to freeze and remove it - it damages the chip and all the information it stores is lost immediately. This is the only proven technology today that can protect encryption keys (More on TPM technology: 5 functions of TPM you did not know about).

Interesting: One of an early version of cryptochips was hacked by Cristopher Tarnovsky in 2010. The hack required very high level of expertise and physical possession of the chip. This hack does not work anymore with the new hardwares.

What about stealing the encryption keys?

Good question. There are some companies that use cryptochip (they call it security card or trustchip, this is the very same thing) and put the keys into the chip at production. The keys are safe inside the cryptochip, it is no question, but can be compromised BEFORE they put it into the chip.

Secfone has its own method. Secfone does not put keys into the cryptochip, but uses cryptochip's functions to generate the keys for itself at production. What does it mean?

1. Keys needed to decrypt the information that arrives to the device NEVER leave the safe storage of cryptochip.
2. Keys can not be stolen from the factory or from a sysadmin.
3. Nobody knows the keys (producer of the cryptocard, Secfone, the customer, nobody)

Interesting: Cryptochip is a military-grade technology under special export regulations. Strict legislation apply to keep information on who possesses the technology. It can not be exported to "sensitive" countries. 

Now the keys are safe. However, there are more layers of security in Secfone, I will write a post about them soon.

Thanks for reading. If you found this blog post interesting, please spread the word.

Cryptohip, security card or trustchip

As mobile communication encryption is getting more and more important, several companies announce their solutions build around micro SD security cards. You get this special micro SD card (security card, cryptocard or trust chip, several names for the very same hardware piece), put it into your smart phone's micro SD slot, and your communication is secured. Or not?

With this new development a myth arose, namely that all micro SD security card based solution provides eavesdrop-proof mobile communication. These systems are more secure than purely software based solutions, that's no question. However using a micro SD security card in a mobile encryption solution does not guarantee eavesdrop-proof communication.

Anyone who thinks it over comes to this conclusion. What happens if a smart phone has a micro SD card with an integrated trust chip or security chip in its micro SD card slot, but a spy ware running on the phone reaches the phone's microphone during calls? The spyware records the conversation, and the conversation is tapped before it even gets to the trust chip. Or what if the trust chip uses standard public key (PKI) encryption, and sends out keys needed to encrypt messages? Well, it is a big help for anyone who tries to crack into the system. Knowing the encryption key significantly reduces the time to figure out the decryption key, therefore to get the message.

Encrypted mobile communication solution has to be chosen based on technical implementation of the encryption system, not based on marketing buzzwords. 100% percent security can be reached only with triple level protection, when a hardware - micro SD cryptocard - protects the encryption keys, a software - an app running on the smart phone - protects against malware and spyware, and a unique encryption solution, that provides eavesdrop-proof communication.

If a company does not take this into consideration, choosing a wrong solution will hurt badly sooner or later.