RSA or DSA?

http://www.linuxquestions.org/questions/linux-security-4/which-is-better-rsa-or-dsa-public-key-12593/
Http://leaf.dragonflybsd.org/mailarchive/users/2005-01/msg00140.html
Http://www.seedmuse.com/rsa_edit.htm

So, what's "(b) RSA is just a better protocol [(ALGORIGHM)]"?

From:	Adrian Bocaniciu <[email protected]>
Date:	Tue, Jan 2005 20:27:22 +0000

 I ' ve read a few pieces which recommend RSA over DSA, although most re:rsa vs Dsacontent-type:text/plain; charset=iso-8859-1; Format=flowedcontent-transfer-encoding:7bitkris Maglione wrote: > So, What's on "(b) RSA is just a better protocol [( ALGORIGHM)] "?  > I ' ve read a few pieces which recommend RSA over DSA, although most > Crypto programs (openssl/ssh etc.) say RSA is DEPRICATED/A last resort.    > Any insights?  Neither DSA nor RSA is deprecated. Both algorithms is OK to use for digital signatures (i.e. the signatures cannot is forged now or in the near future), if    Their parameters, i.e. the key lengths, is chosen correctly. The RSA algorithm can also was used for Public-key encryption, but that's not recommended, because there was better ways t O accomplish that and also because some older variants of the using RSA for encryption is broken. (despite, most HTTPS Web sites is still using obsolete SSL libraries or configurations, which also using RSA for Encry PtIon, not only for authentication).  DSA and RSA is the only digital signature algorithms that is both standardized and free from patents.  There is a time when RSA is not recommended because it is covered by a patent and now the patent has expired.  There is also other digital signature algorithms that is better for some applications, e.g. Rabin-williams, which can  Verified much faster than RSA, but they was not standardized (except in IEEE 1363, which was not widely implemented yet). Other algorithms, like those using elliptic curves, is claimed to being covered by US patents, so they cannot is recommende    D While there is free alternatives.  For RSA, a 1536-bit key pair are recommended now for the uses e.g. SSH Public-key authentication, but longer keys shall be  Used for signing documents, should not being forged even after many years. Nevertheless, most Web sites this use HTTPS, has only 1024-bit RSA key pairs, those is still reasonably secure for now, But in a fewYears they would become breakable. An 1536-bit RSA public/private key pair requires about the same time for breaking as a 90-bit key of a secret-key Algorith M. Nonetheless, in reality 1536-bit RSA was much more secure than 90-bit, because either a huge memory (much beyond what I  s currently possible) is needed for the computation or, if the memory is unavailable, the computation becomes much slower,    So the RSA key is equivalent in strength with a longer secret key. RSA is more appropriate-signing certificates, because it can be verified faster, but for the authentication of the INI Tial message exchange in network connection establishments, like in IPsec, Tls/ssl or SSH, DSA can be better, because ther E is an equal number of signing and verification operations, so only the sum of the execution times for signing and Verif  Ication matters. DSA has the advantage that it had the same security as RSA at a shorter key length, i.e. 1280-bit DSA have about the same s Ecurity as 1536-bIt RSA. For this reason I always use 1280-bit DSA key pairs for SSH authentication, i.e. the keys is generated with "Ssh-keygen-    T Dsa-b ", both for the server host key and for the users ' workstations. DSA has a disadvantage-is not a property of the algorithm but only of its implementation in OpenSSL, OpenSSH and othe R common Programs, it has several parameters that must is increased simultaneously for better security, but applications L  Ike Ssh-keygen Let's specify only the key length and they keep the other parameters unchanged. Because of that's it is absolutely useless to increase the DSA key length beyond 1280-bit, Because the security was not Impro  Ven.       On the other hand, with RSA you can specify 2048-bit, 3072-bit or longer key pairs, if your so desire. Best regards!

RSA or DSA?