Timeline for Using SHA-512 for encryption/decryption
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
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| Oct 26, 2016 at 10:32 | comment | added | CodesInChaos | A high performance implementation of AES-128-CTR using the AES-NI instructions will run at about 1.33 cpb, or 2.5 GB/s. Without AES-NI it should cost about 11.5 cpb. SHA-512 hashes at about 11 cpb, but you need to double that for encryption, so you're at 22 cpb or 155 MB/s. (Single threaded, Sandy Bridge at 3.4 GHz, Turbo Boost disabled, costs taken from the hydra7 system on eBACS) So AES is almost twice as fast without using AES-NI and about 15x faster using AES-NI. | |
| Sep 28, 2016 at 14:14 | vote | accept | Douglas | ||
| Sep 27, 2016 at 3:36 | answer | added | Barmak Shemirani | timeline score: 3 | |
| Sep 26, 2016 at 14:24 | comment | added | Douglas | @BarmakShemirani It's feeding back the output as state to compute the next value that will be xored with the plaintext. I wrote it for fun and learning, but it's much faster than AES on my i7-2600. I get 160MB/s vs at most 121MB/s for aes-128 cbc. Link: imgur.com/UO3pQPB | |
| Sep 26, 2016 at 1:56 | comment | added | Barmak Shemirani | It is possible to use SHA512 as block cipher for encryption in OFB mode. I don't see how it could be done in CBC mode. And I don't see what your SHA512 function is doing. Either way, AES is faster than SHA512, or even SHA256. AES also has its own instruction set on newer chips, this makes AES even faster. AES can also be used in different modes like CTR mode, this is often time required in real applications. I would suggest using SHA-2 for what SHA-2 is intended for, and using AES for what AES is intended for. | |
| Sep 24, 2016 at 23:32 | comment | added | Douglas | @JS1 Yes, it's symmetric and requires the key and IV to be known when decrypting it. But the IV is usually stored with the file. So you normally only know the key and read the IV. | |
| Sep 24, 2016 at 21:55 | comment | added | JS1 | Does the decrypter know the 256 bit key and the 512 bit initial value already? | |
| Sep 24, 2016 at 15:22 | history | asked | Douglas | CC BY-SA 3.0 |