Is It Time To Upgrade To ECC SSL Certificate (ECDSA)?

You possibly know that Let’s Encrypt (read CertBot) now provides ECDSA certificate. Some already arguing that ECDSA consumes much less resources than older RSA certificate. Some online testing tool giving lesser marks for having RSA. ECC Certificate is Newer Than RSA SSL Cert. Definitely the ECC is Secure & Faster. Is It Time To Upgrade To ECC SSL Certificate (ECDSA)?

 

Technologies Behind ECC SSL Certificate (ECDSA) and RSA Based SSL Certificate

 

We talked about Encryption and Decryption, Digital Signature, Role of Elliptical Cryptography (ECC) in Software Defined. Let us go in to slight details of ECC and RSA.

 
RSA
 

RSA is the initial letters of the surnames of who first publicly described the algorithm in 1977. RSA is a relatively slow algorithm. The RSA algorithm involves 4 steps – key generation, key distribution, encryption and decryption.
RSA involves a public key and a private key. The public key can be known by everyone and is used for encrypting messages. The intention is that messages encrypted with the public key can only be decrypted in a reasonable amount of time using the private key. There are some known attacks.

 
ECDSA
 

ECDSA stands for Elliptic Curve Digital Signature Algorithm. It is a variant of the Digital Signature Algorithm (DSA) which uses elliptic curve cryptography. DSA was proposed by the National Institute of Standards and Technology (NIST) in August 1991. It is quite different than RSA. ECDSA signatures and public keys are much smaller than RSA signatures and public keys of similar security levels. If you compare a 192-bit ECDSA curve compared to a 1k RSA key (which are roughly the same security level; the 192-bit ECDSA curve is probably a bit stronger); then the RSA signature and public key can be expressed in 128 bytes each (assuming that user is willing to use a space-saving format for the public key, rather than using the standard PKCS format); the ECDSA signature would be 48 bytes, and the public key would be 25 bytes.

 

Is It Time To Upgrade To ECC SSL Certificate (ECDSA)?

 

ECDSA signature verification is slower than RSA with reasonable security levels. That is the one place that RSA is great. We can verify RSA signatures rather faster than you can verify an ECDSA signature. According to this web page, on their test environment, 2k RSA signature verification took 0.16msec, while 256-bit ECDSA signature verification took 8.53msec (see the page for the details on the platform they were testing it) :

Although 256-bit ECDSA is probably a bit stronger than 2k RSA, still if the difference isn’t quite 50x, RSA is still faster. But according to the ECRYPT II recommendations on key length, a 256-bit elliptic curve key provides as much protection as a 3,248-bit asymmetric key. Typical RSA keys in website certificates are 2048-bits. In that case, on our servers, using an ECDSA certificate saves a lot of CPU cycles. This is a good read :

Here is online testing tool :

Not all CA supports ECC SSL certificate. Not all OS – Browser, web server software has full compatibility :

It is possible to use both RSA and ECDSA certificates on Nginx web server. From the point of SEO, some bots can fail with only ECC SSL certificate. It is not a big matter if you have a popular website. Full ECC may not be compatible with all tools. We lack idea about combining both RSA and ECDSA certificate. You can wait till SSL Labs test warns for RSA.