Forum ©XSIBackup: ©VMWare ©ESXi Backup Software

admin

Administrator

Registered: 2017-04-21

Posts: 2,055

Intel SHA-1 extensions

As many of you already know, (c)XSIBackup in general: Pro and DC makes use of the SHA-1 algorithm to index blocks of data. There are multiple reasons for that: it has excellent dispersion properties, it is available in OpenSSL and it's fast.

SHA-1 was conceived for encryption, not just for uniqueness, like: Murmur or Cityhash, thus we are playing an extra CPU cost for a feature that (c)XSIBackup does not need. That is true, but there is an extra fact that is quite important in the equation.

Most Intel processors that are used in servers nowadays incorporate native ASM extensions for the SHA-1 algorithm and OpenSSL takes advantage of those extensions, making SHA-1 be extremely fast when it comes to hash data.

Mathieu

Member

Registered: 2021-04-20

Posts: 7

Re: Intel SHA-1 extensions

How can we determine if our processor incorporates the extension for SHA-1 algorithm?

We have an Intel(R) Xeon(R) Silver 4210R CPU @ 2.40GHz, and we can find on Intel website that this CPU incorporates the following extensions: Intel® SSE4.2, Intel® AVX, Intel® AVX2, Intel® AVX-512.

admin

Administrator

Registered: 2017-04-21

Posts: 2,055

Re: Intel SHA-1 extensions

All modern CPUs do. Only some old low end ones, like some Atom processors (just thinking loud) could still be found without them.