Forum ©XSIBackup: ©VMWare ©ESXi Backup Software

admin

Administrator

Registered: 2017-04-21

Posts: 2,072

Intel SHA-1 extensions

As many of you already know, [b](c)XSIBackup[/b] in general: [b]Pro[/b] and [b]DC[/b] makes use of the [b]SHA-1[/b] 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.

[b]SHA-1[/b] was conceived for encryption, not just for uniqueness, like: Murmur or Cityhash, thus we are playing an extra CPU cost for a feature that [b](c)XSIBackup[/b] 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 [b][url=https://software.intel.com/en-us/articles/intel-sha-extensions]native ASM extensions[/url][/b] 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: 2,072

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.