BYOE
BYOK makes the best of the cloud provider's encryption offering, by giving the customer ultimate control over its key. But is the customer happy with the encryption provided?
Bearing in mind that balance between security and efficiency, you might prefer a higher level of encryption than that used by the cloud provider's security system, or you might find the encryption mechanism is adding latency or inconvenience and would rather opt for greater nimbleness at the cost of lighter encryption. In this case you could go a step further and employ your own encryption algorithms or processes. Welcome to the domain of BYOE (Bring Your Own Encryption).
Again, we must balance security against efficiency. Take the example of an enterprise using the cloud for deep mining its sensitive customer data. This requires so much computing power that only a cloud provider can do the job, and that means trusting private data to be processed in a cloud service. This could infringe regulations, unless the data is protected by suitable encryption. But how can the data be processed if the provider cannot read it?
Taking the WW2 example above: if a Japanese wireless operator was asked to edit the Native American message so a shortened version could be sent to HQ for cryptanalysis, any attempt to edit an unknown language would create gobbledygook, because translation is not a "homomorphic mapping".
Homomorphic encryption means that one can perform certain processes on the encrypted data, and the same processes will be performed on the source data without any need to de-crypt the encrypted data. This usually implies arithmetical processes – so the data mining software can do its mining on the encrypted data file while it remains encrypted, and the output data, when decrypted, will be the same output as if the data had been processed without any intervening encryption.
It is like operating one of those automatic coffee vendors that grinds the beans, heats the water and adds milk and sugar according to which button was pressed – you do not know what type of coffee bean is used, whether it's tap, filtered or spring water, or whether the milk is whole cream, skimmed or soya. All you know is that what comes out will be a cappuccino with no sugar.
In the data mining example, what comes out might be a neat spreadsheet summary of customers' average buying habits based on millions of past transactions, without a single personal transaction detail being visible to the cloud's provider.
The problem with the cloud provider allowing users to choose their own encryption is that the provider's security platform has to be able to support the chosen encryption system. As an interim measure, the provider might offer a choice from a range of encryption options that have been tested for compatibility with the cloud offering, but that still requires one to trust another's choice of encryption algorithms. A full homomorphic offering might be vital for one operation, but a waste of money and effort for a whole lot of other processes.
The call for standards
So what is needed for BYOE to become a practical solution is a global standard cloud security platform that any encryption offering can be registered for and supported by that platform. The customer chooses a cloud offering for its services and for its certified "XYZ standard" security platform, then the customer goes shopping for an "XYZ certified" encryption system that matches its particular balance between security and practicality.
Just as in the BYOD revolution, this decision need not be made at an enterprise level, or even by the IT department. BYOE, if sufficiently standardised, could become the responsibility of the department, team or individual user – just as you can bring your own device to the office, you could ultimately take personal responsibility for your own data security.
What if you prefer to use your very own implementation of encryption algorithms? All the more reason to want a standard interface! This approach is not so new for those of us who remember the Java J2EE Crypto library – as long as we complied with the published interfaces, anyone could use their own crypto functions.
This "the network is the computer" ideology becomes all the more relevant in the cloud age. As the computer industry has learned over the past 40 years, commonly accepted standards and architecture (for example the Von Neumamm model or J2EE Crypto) play a key role in enabling progress.
Creating such a standard is just one more aspect to the mission of preventing the cloud from fragmenting into incompatible offerings and vendor lock-in by rival providers. BYOE could prove every bit as disruptive as BYOD – unless the industry can ensure that users choose their encryption from a set of globally sanctioned and standardised encryption systems or processes.
If business is to reap the full benefits promised by cloud services, it must have the foundation of such an open cloud environment.
- Dr. Hongwen Zhang is chair of the Security Working Group, CloudEthernet Forum
