Viewing profile — RaisingSpear

From memory, the SpacemiT K1 doesn't support extensions like Zvkt? EDIT: okay, looks like the official documentation lists it, but many places I looked didn't. Maybe it wasn't bein…

If you scale up the multipliers, you should be able to eliminate the variable shift, which would reduce the lookup table to 512 bytes.

For CPUs that support AVX-512 VBMI, there's a faster reciprocal-based approach: https://avereniect.github.io/2023/04/29/uint8_division_using... A VBMI2 example implementation can b…

I suspect Intel uses 32x32b multipliers instead of his theorised 16x16b, just that it only has one every second lane. It lines up more closely with VPMULLQ, and it seems odd that P…

> Does every dev need to write the same line now? Yes. > Or should your one-liner be a library? Definitely not. Particularly if I can write the one-liner faster than it takes one t…

Yeah, you can write it in less than a minute: const tryNew = (f, ...a) => { try { return new f(...a); } catch(x) { return undefined; } }; const myUrl = tryNew(URL, ' http://example…

Search engines: they scrape the web, but get narky when scraped themselves.

Tangentially related, but I've had a case where GCC 9.4.0 shipped a broken arm_acle.h header [ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100985 ] - code which includes the heade…

I think we're talking past each other a bit here. If I were trying to phish someone, I wouldn't attack the public key crypto part, so how domains come into play during authenticati…

From my understanding, FIDO isn't MFA though (the authenticator may present its own local challenge, but I don't think the remote party can mandate it). There's also the issue of h…

The phisher can just pass on whatever you sign, and capture the token the server sends back. Sure, you can probably come up with some non-HTTPS scheme that can address this, but I …

> That's why I qualified it with "certificate-based". The private key never leaves the device Except that phishing doesn't require the private key - it just needs to echo back the …

> I don't think phishing is such an obscure scenario. For a typical person, maybe, but for a tech-minded individual who understands security, data entropy and what /dev/random is? …

But password managers typically don't send keyboard commands to fill in a password, so a physical device would be useless. > There are plenty of scenarios where MFA is more secure …

I don't quite understand what you're saying, but it should be possible to infer the length from the number of bytes received. Assuming n is an integer: * 5n bytes received = 4n byt…

Padding is actually not really necessary in base64, as you can infer the length from the number of characters received. Unfortunately for Z85, they made the highly questionable dec…

> The four octets SHALL be treated as an unsigned 32-bit integer in network byte order (big endian). The five characters SHALL be output from most significant to least significant …

Did the challenge limit submissions to only using SSE2? Seems odd, given the prevalence of SSE4.2 support. PMULUDQ is in SSE2, though I haven't checked if that's usable for the pro…

POPCNT doesn't exist in AVX prior to Icelake, so using other techniques there is sensible. Also, that's POPCNT, not LZCNT.

> There are some times when you're doing these operations in large vector types (like AVX), in parallel, when falling back to the SWAR techniques can actually be faster because of …

> if your computer ever gets compromised If that happens, nothing will save you. The malware can just grab your session tokens whenever you log in, then do whatever it pleases.

> So far I couldn't exceed 1 GB/s/core [4], so more research is needed. If you have any ideas - I am all ears! I don't know much about the space you're working in, but some things …

> Under no circumstances should FLAC level 5 decode be faster than FLAC level 0 decode. I don't know about FLAC, but from my knowledge of compression, this result seems sensible to…