Problem - Kevin Tafuro

Elliptic curve cryptography can provide the same levels of security with much smaller
key sizes and with faster algorithms, but this type of cryptography is not yet in widespread
use.
Discussion
Be sure to see the general recommendations for using public key cryptography
in Recipe 7.1.
Security-wise, there’s no real reason to choose any one of the common algorithms
over the others. There are also no intellectual property restrictions on any of these
algorithms (though there may be on some elliptic curve variants). RSA definitely sees
the most widespread use.
RSA private key operations can be made much faster than operations in other algorithms,
which is a major reason it’s preferred in many circumstances. Public key
operations across RSA and the two other major algorithms (Diffie-Hellman and
DSA) tend to be about the same speed.
When signing messages, RSA tends to be about the same speed or perhaps a bit
slower than DSA, but it is about 10 times faster for verification, if implemented properly.
RSA is generally much preferable for key establishment, because some protocols
can minimize server load better if they’re based on RSA.
Elliptic curve cryptography is appealing in terms of efficiency, but there is a practical
downside in that the standard in this space (IEEE P1363) requires licensing patents
from Certicom. We believe you can probably implement nonstandard yet still secure
elliptic curve cryptosystems that completely avoid any patent restrictions, but we
would never pursue such a thing without first obtaining legal counsel.
See Also
Recipe 7.1
7.3 Selecting Public Key Sizes
Problem
You’ve decided to use public key cryptography, and you need to know what size
numbers you should use in your system. For example, if you want to use RSA,
should you use 512-bit RSA or 4,096-bit RSA?
312 | Chapter 7: Public Key Cryptography
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