[IheartApplesDix]

I'm not sure how reduced memory requirements are a benefit to encryption. Are there really any low end systems still in use today that actually have issues with memory usage? Even $150 notebooks come with 1 gig of ram. This seems more like it would help save ram on interception devices like the Narus Device or the huge datacenters owned by the NSA, which have a huge issue with storing all the data required to intercept and decrypt eavesdropped communications reliably.

[theatrus2]

The last system where I used SHA-256 had 16KiB of RAM (and 128KiB of direct-mapped flash). Yes, memory use for security algorithms is important.

[s353]

I think of reduced memory requirements as a benefit to every application, including encryption. That's because nearly every application I use competes for memory; I also use memory as general storage media for stuff for which I want fast I/O and/or don't need to save permanently (e.g. mfs or tmpfs mounts). I think of memory as a precious resource.

[Dylan16807]

That doesn't really apply to memory use on the order of a single kilobyte. You're not going to be hashing many different streams at once.

[marshray]

And why not? Ever considered a busy SSL offload device or VPN appliance?

A kilobyte here, a kilobyte there, and pretty soon you're talking real memory!

[Dylan16807]

I think something handling a TCP stream has better things to worry about than an extra buffer smaller than a single packet.

[marshray]

Well, you're wrong, at least for a specific segment of hardware and software on the market. The size of a packet is not related to the acceptable per-connection overhead. Some network devices like ASIC-accelerated routers can't handle any per-connection state.

If you don't believe me, hop on any kernel development mailing list and try to convince them they could solve world hunger by only adding 1 KB overhead to the TCP socket structure that tracks actve connection states.

[haberman]

Can't upvote this enough. When you live at the bottom of the stack, you can't be cavalier about your constant overheads. Practically any overhead you can think of is going to be multiplied by "n" in someone's O(n).

[IheartApplesDix]

Think of encryption as more secure the harder it is to do. Optimizing encryption for the benefit of other applications is backwards.

[Heliosmaster]

Think about RSA. Harder Encryption (computationally) is achieved with a high e. Too bad that Wiener in 1990 proved that if d (private key) is small enough we can easily crack it using continued fractions.

[dchest]

Think smart cards.

[dlitz]

Or RFID. If you actually want to build secure RFID devices, you need really low-power crypto.

[IheartApplesDix]

Some kind of next generation smart card, no doubt. Like a universal ID, replacement for mobile payment methods and Apple Passbook, since people don't trust their carriers to be reliable, unbiased communication networks or platforms... ah yes, I see.

[Daniel_Newby]

> Even $150 notebooks come with 1 gig of ram.

The issue is with the processor's cache memory, which is small, typically 64 kiB or so. (The TLB cache is also important.) Even a few hundred bytes savings can give an important improvement in speed amd power consumption.