Difference between symmetrical and asymmetrical keys for encryption?
As a continuation from our previous article on symmetrical encryption we shall now look at other methods of encrypting data. Although symmetrical is fast and effective it was not practical for some uses as although it kept the transfer of information safe it would not provide
%100 proof that the message came from that originator as the one private key could be shared amongst a group for a purpose. If you had a problem with a key or it had been compromised that was shared between 10 individuals, then you would have to replace 45 keys within that group. For larger organisations trying to securely communicate to even larger organisation this method was impractical. The resolution was to two
have two separate keys, one private to the individual and the other transferred to authorised parties. Splitting the code allowed for greater flexibility as the details of the public could be fully known without compromising security as the code of the private key was kept away from view. This means that if a private key is compromised or is no longer valid it can replace without the need for recalling all the related keys as only the internal code of the private needs updating. Even if another 3 party had the public key, the private key would not confirm the trust. This is called asymmetrical encryption as the keys are not same.
Provide non-repudiation using asymmetrical keys?
This also provides proof that the message came from there on who sent it. If the two keys match from sender and receiver then it provides certainty that source and the originator is one and the same. This useful in business to provide audit trails of agreements and conditions of trade. It also guarantees that no-one else could read the message as without the public key they would not be given access.
How are asymmetrical keys used?
There are several different varieties of this such as:
- RSA is most commonly used for messaging,
- Diffie Hellman which provides a safe method of transferring keys.
- Elliptic Key Curve allows for greater strength of encryption but in a shorter code. This is used in such items as smart cards and wireless technologies.
As asymmetrical encryption requires greater computations it can also be quite slow. In response there are several hybrid technologies the best of both worlds of asymmetrical and symmetrical. HMAC is a Message Authentication Code which is a check sum (small piece of data used to check errors in transmission) that is embedded into a message to prove authenticity.
As digital security becomes increasingly important due to the number of high-profile data breaches, then encryption will be more widely adopted. It is important to realise the basis for the technology and how it is best used.
For those needing advice with this see our Services page. Next in the series “encryption through email”.
See our previous articles on encryption.