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Comment: Re:Why do we have all these custom PRNGs? (Score 1) 138

by petermgreen (#46485859) Attached to: Weak Apple PRNG Threatens iOS Exploit Mitigations

IMO there are a few problems

1: As you say lack of sufficient eduaction on what random and urandom do
2: linux doesn't have a middle of the road option. /dev/random is overly paranoid allowing the output to be blocked if it estimates there is less enropy coming in than going out. /dev/urandom is overly loose not blocking even if the system has never gathered enough entropy to give reasonablly secure randomness. What you really want for most crypto purposes is something that will wait for sufficient seed data before starting but that will free-run after that.
3: Sometimes the overall system design means there is no good option, you either proceed with dubious randomness or you hang forever.

Comment: Re:all PRNGs are deterministic (Score 4, Informative) 138

by petermgreen (#46484235) Attached to: Weak Apple PRNG Threatens iOS Exploit Mitigations

For a CSPRNG* the primary aim is to make it computationally infeasable for an attacker to predict the output even if the attacker has an aribiterally long sample of the output and even if the attacker knows how much output has been requested from the prng since it started.

To do this places demands on both the prng itself (it must be computationally infeasible to reverse the operations done by the prng and hence determine it's internal state from an output sample) and on the seed data fed into the prng (it must be sufficiently unknown/unpredictable to the attacker that the attacker can't obtain the seed state through a combination of his knowlage of the state of the system and brute force checking of different seed values)

Afaict it is the latter where things usually go wrong.

* Cryptographically secure psuedo-random number generator.

Comment: Re:Hmm (Score 1) 185

I mean, just look at the devastation non-native species are causing in various nations. They certify they can contain these creatures forever and ever?

Notice that it's small animals being invasive while the megafauna are often endangered even on their home ground?

Megafauna move slowly, breed very slowly and are easy to spot. So it's pretty easy to hunt and kill them at a rate much faster than they can breed.

Comment: Re:Reassembling the Soviet Union (Score 1) 302

by petermgreen (#46481325) Attached to: Russia Blocks Internet Sites of Putin Critics

What is the upside of existence of Ukraine as separate state? And any other national state for that matter..

The larger an empire gets the less representation each citizen of that empire has and the harder it gets to topple corrupt rulers. It can also mean that entities just outside the empire come under a lot of pressure to become part of it (in turn making the empire ever larger and more powefull).

Which I get the impression is the big problem for ukraine. It's presumablly very difficult to find compromises in politics when one side wants to be part of the russian block, the other side wants to be part of the EU and being part of the two is mutually exclusive.

Comment: Re:Reassembling the Soviet Union (Score 2) 302

by petermgreen (#46481203) Attached to: Russia Blocks Internet Sites of Putin Critics

Putin’s long game? Meet the Eurasian Union [bostonglobe.com]


Putin aside I can see why the russians would not much like the idea of going from being the dominant force in a block to being the ones stuck just outside it

* buy a £20 item, pay £4 VAT plus £10 fee for collecting the VAT is the sort of experiance i've had when buying from outside the EU.
** Strictly speaking it's the schengen area rather than the EU per-se but there are only a handful of countries that are in one but not the other.

Comment: Re:A 25% increase is ridiculous (Score 1) 271

by petermgreen (#46480701) Attached to: Amazon Hikes Prime Membership Fee

At 100/year its still a steal if you order a lot (I've ordered furniture from amazon using Prime... 2 day free shipping on a desk? Sectional couch? TV?

I wonder how much more the two day shipping really costs them than the standard free shipping. To an extent if a lot of people buying the struff have prime subscriptions I would expect them to just build the cost of said two day shipping into their prices.

Comment: Re:That's nice - but it's based in the US (Score 1) 329

by petermgreen (#46476015) Attached to: 1GB of Google Drive Storage Now Costs Only $0.02 Per Month

at least on paper...

And therin lies the problem, if a megacorp whose headquarters are in the US is given the choice between handing the data over to the US government (and hence breaking EU law but probablly not being punished for it since the EU government won't know it happened) or refusing to hand the data over and getting punished by the US governemnent for doing so which do you think they will choose?

Comment: Re:OIF-MSA-100GLH = 1.2Tbs bidirectional via 24MPO (Score 1) 101

by petermgreen (#46473877) Attached to: Intel Rolling Out 800Gbps Cables This Year

Over long distances your main costs are the fiber and optical amplifiers, so fancy tricks at the transmitter and receiver to get more out of said infrastructure make a lot of sense.

Over short distances the fiber is a smaller part of the overall cost and so it's often cheaper to just lay more fiber than to bother with the fancy tricks.

Comment: Re:Why not massively subsidize the Solar Industry? (Score 1) 707

Per watt of what?

Per watt of maximum production of the panels under unrelistic condions used in the vendors datasheet?
Per watt of maximum production of the panels on a real site?
Per watt of average production of the panels on a real site?
Per watt of expected production at the time the grid needs the power most*?

* This is especially a problem in cooler climates where the peak load is heating rather than aircon.

Comment: Re:Replaced by what? (Score 1) 707

Oil prices are vastly different than oil costs for most oil producers. We need to worry, then, only of beating oil prices

Prices in a competitive market are driven by costs BUT it's not the average costs that matter, it's the marginal costs. If demand exceeds supply then the price will rise, the rising price will have two affects, firstly it will decrease demand, secondly it will cause sources that were previously non-viable to be brought online, this will bring the market back into balance.

Similarly if supply exceeds demand then prices will fall causing sources that were previously viable to become non-viable and also increasing demand and brining the market back into balance.

Of course in both cases there are time delays and hence inherent instability. on both the supply and demand side so short term fluctuations are inevitable.

So if you want to drive out the majority of use of resource x you have to beat the cost of the majority of production of that resource to drive down the price of the resource to where the majority of production is non-viable.

Comment: Re:Interesting parallel (Score 1) 132

by petermgreen (#46468173) Attached to: US Court Freezes Assets of Mt. Gox CEO

Makes me wonder why people in say, EVE, aren't held liable or arrested for sweeping in and taking over an entire faction and claiming everything as their own.

Eve online is a game, participents in the game knew or should have known that anything in the game is subject to the rules of the game and the whims of the games owners. They also knew or should have known that they were forbidden from exchanging those in-game "assets" for anything outside the game.

MT gox traders on the other hand have put their money and bitcoins in trust with the exchange so they can trade them with each other more easilly. The exchange has broken that trust either by stealing the bitcoins themselves or by incompetently allowing large scale heists.

Comment: Re:Comcast's DNS has been spotty for a while (Score 1) 349

by petermgreen (#46468125) Attached to: Crowdsourcing Confirms: Websites Inaccessible on Comcast

which pushes the cost onto innocent third party service providers

The records higher up the chain (e.g. on the root and tld servers) can still have long ttls and be cached appropriately even if the records at the bottom of the chain have short ttls. so the only person it's really "pushing costs on" is the end users dns provider (usually thier ISP).

The fact that google give away dns service for free without trying to inject any advertising makes me think that the "costs being pushed" onto the users ISP are pretty trivial.

primarily, that it redirects based on where the user's DNS resolver lies, which may be on the opposite side of the country from the user

That is certainly a disadvantage, more so for some sites than others (if you only have a handful of locations per continent then it's probablly not going to make much difference for you).

There are proposals to fix this issue but it will take time for them to be adopted.

For web-based traffic, properly implemented redirects are typically the best option.

Redirects are a good choice for downloads and possiblly videos (for videos custom page generation also seems to be a common soloution) but if you try and use them for pages you will end up with users storing permanent references to individual servers in their bookmarks and you also have the problem that you have to serve the redirects from somewhere (which brings us back to the problem of poor retry handling). IMO these issues make redirects an unacceptable soloution for geographic detection and fallback with web pages.

For other services with a dedicated client, there are much better options that can be implemented, and can also provide a much better user experience.

Agreed if you have a dedicated client you have a lot more options.
