The security levels for RSA are based on the strongest known attacks against RSA compared to amount of processing that would be needed to break symmetric encryption algorithms. The equation NIST recommends to compute approximate length for key is found in FIPS 140-2 Implementation Guidance Question 7.5. It is:

Apr 10, 2012 · Adequate security was defined as the security offered by DES in 1982. There are several factors that influence the choice of the key length, for example the life span of the data you want to protect, the estimation of the computational resources (consider Moore's law) and the cryptanalytic advances through the years (Integer factorisation ...

With RSA the padding is essential for its core function. RSA has a lot of mathematical structure, which leads to weaknesses. Using correct padding prevents those weaknesses. For example RSA Encryption padding is randomized, ensuring that the same message encrypted multiple times looks different each time.

Jan 27, 2023 · NIST SP 800-57 Part 1 rev 5 section 5.6.1.1 gives following comparison between different encryption types. For example, it shows that 3TDEA, RSA-2048, ECC224 provides security strength of 112 bits....

Jun 5, 2017 · The key size is therefore easy: AES-256 has close to 256 bits of security while RSA only offers about 112 bits of security. In that respect AES-256 has RSA-2048 completely beat. [EDIT 2023] Although I would strongly suggest 3072 or 4096 bit keys for RSA nowadays, performing close to $2^{112}$ operations to crack just one key is outside the ...

May 18, 2017 · Properly constructed RSA padding (such as OAEP) does this, and more generally (pseudo-)randomizes the plaintext in such a way that what actually gets encrypted by the "textbook" part of RSA looks effectively like a random number, thereby defeating both this and various other attacks on textbook RSA.

Aug 31, 2021 · I can't find any reference discussing asymptotic RSA security with a notation like $1^k$ that specify a minimum $\lvert p-q\rvert$. That's because: Increasing $\delta$ past some point demonstrably decreases security.

Apr 18, 2018 · $\begingroup$ Generally it is easier to attack the system around RSA than RSA itself, unless RSA is not implemented well (textbook RSA, small key size). $\endgroup$ – Maarten Bodewes ♦ Commented Apr 18, 2018 at 7:40

May 3, 2018 · One of the attacks on plain RSA involves a sender who encrypts two related messages using the same public key. Formulate an appropriate definition of security ruling out such attacks.And show that any CPA-secure public-key encryption scheme satisfies your definition. What does formulating an appropriate definition of security mean?

May 26, 2021 · I am in the process of created a signing certificate and i have an option of RSA-4096 or RSA-3072. Is there much difference in security between the two? I know people say RSA-3072 should be good until 2030. But people may also prefer the high security. But if it makes a big difference on speed, they may not.