# How much faster in symmetric cryptography compared to asymmetric cryptography? [closed]

I know that symmetric cryptography is faster than asymmetric, but on average how much faster would it be if you were encrypting and decrypting a 2MB file?

## closed as too broad by Maarten Bodewes♦, yyyyyyy, e-sushiJun 28 '17 at 15:15

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• The differentiation is more because they do different things, as for comparing speeds you would need to be more exact about which cryptographic systems you are comparing. – daniel Jun 27 '17 at 14:55
• Data is rarely encrypted with asymmetric encryption. See hybrid encryption. – tylo Jun 27 '17 at 15:30
• The 2 MB file very likely won't be 2 MB after encryption with asymmetric algorithms. Concatenated RSA is one of the most efficient asymmetric encryption schemes - space wise - that I know of, and it is both horribly slow and still adds significant overhead. – Maarten Bodewes Jun 27 '17 at 15:39
• It's not practical and not appropriate. Speed wise it can be slower 1000 times. RSA is secured with padding for your files will be quite inflated. Asymmetric algorithms are used for authentication, and symmetric for key derivations, CMAC and content encryption. – VovCA Jun 27 '17 at 18:34
• related question – fgrieu Jun 27 '17 at 20:30

## 2 Answers

The page https://www.cryptopp.com/benchmarks.html has a comparison of the speeds of a number of different algorithms. You will have to do a little math to covert to the time necessary to encrypt a 2MB file, but this should give you the base information necessary.

In general case, symmetric cryptography is not faster that asymmetric ones. For example with this asymmetric cryptosystem we are able to encrypt more than $40Gb$ per second. This huge number is not comparable with slow systems such as $1024$-bit RSA that is $40Kb$. It is attractive that throughput of encryption with AES-$128$ is less than $5Gb$ per second(according to the mentioned paper).

• Except that the MQQ cryptosystem that you link to is broken. – Aleph Jun 27 '17 at 21:45
• @Aleph Not as a challenging reply but because I'm actually interested, could you please give proper references? thanks – Daniel Jun 27 '17 at 22:04
• @Daniel Search on Google Scholar for the title $\Rightarrow$ click on "cited by" $\Rightarrow$ first link is Algebraic Attack on the MQQ Public Key Cryptosystem. Looking at the other papers citing this (28 in total), I am not convinced this received much attention. – tylo Jun 28 '17 at 11:42
• @tylo There's that, and the work by Perret. I don't think the statement "In general case, symmetric cryptography is not faster that asymmetric ones." is fair. I can't think of any practical (not broken and sufficiently well established) asymmetric schemes which outperform AES. Looking at the benchmarks that the other answer refers to, that situation is pretty clear I think. – Aleph Jun 28 '17 at 15:40