The attack relies on "side channel analysis," in which attackers extract a secret decryption key based on clues leaked by electromagnetic emanations, data caches, or other manifestations of a targeted cryptographic system. In this case, cryptographers can retrieve the private key needed to take control of bitcoins by taking minute measurements of the CPU as it makes transactions using the digital currency. Specifically, by observing the last-level (L3) CPU cache of an Intel processor as it executes as few as 200 signatures, an attacker in many cases has enough data to completely reconstruct the secret key needed to take ownership. The attack exploits the way OpenSSL implements the elliptic curve digital signature algorithm (ECDSA) based on a specific curve known as secp265k1 found in Bitcoin.

"It should be noted that irrespective of the weakness in the Intel processors, cryptographic algorithms are not supposed to leak information," he wrote in an e-mail. "Hence, the fact that we can get data out of the OpenSSL implementation is a weakness in OpenSSL and should be fixed."

Indeed, experts have long recommended a Bitcoin key be used only once, but this advice is routinely ignored. Another measure is to avoid the use of Intel processors, since the attack doesn't work on modern CPUs made by AMD, Yarom said.

Love of money can cause people to do unwise things—like stealing time on your university's resident supercomputer to mine crypto-coins. The Harvard Crimson is carrying the story of someone who did exactly that: an unnamed individual who was discovered using Harvard's Odyssey supercomputing cluster to generate dogecoins.

Calling itself the world's "first virtual currency," Bitcoin offers the …
"Wow," you might say, amazed. Dogecoins are one of the multitude of roll-your-own cryptocurrencies that have lately sprouted like weeds in an unkempt vegetable garden. Like most of them, the code that powers Dogecoin's blockchain and network is forked from Litecoin, which was originally billed as a lighter-weight alternative to Bitcoin. Dogecoin (and Litecoin and Coinye and many others) use the scrypt cryptographic algorithm to generate hashes and drive the currency along; media-darling Bitcoin, on the other hand, is based around a different algorithm (SHA256). The currencies are all similar to each other, though they are (generally) incompatible and (typically) do not interoperate. (There are caveats, but cryptocurrencies are complex and I'm trying to keep this relatively short—check here for the full details on how and why cryptocurrencies work.)

One change in the new SM will be especially consequential for certain customers—and possibly for the entire GPU market. Maxwell restores a key execution resource that was left out of Kepler: the barrel shifter. The absence of this hardware doesn't seem to have negative consequences for graphics, but it means Kepler isn't well-suited to the make-work algorithms used by Litecoin and other digital currencies. AMD's GCN architecture handles this work quite well, and Radeons are currently quite scarce in North America since coin miners have bought up all of the graphics cards. The barrel shifter returns in Maxwell, and Nvidia claims the GM107 can mine digital currencies quite nicely, especially given its focus on power efficiency.

first off thank you for this amazing program

I've been mining on cgminer for a few days at max 15kh/s but now switched to cuda miner since Im using a Nvidia GPU

Would anyone be able to point me to settings that can help my performance (currently getting 100kh/s). My setup is

GTX 770M
i7 4700MQ
24GB RAM
windows 7 x64

Thanks in advance guys!

Really, what other settings? 16x16 with my config gives me only ~200kH/s

Early christmas present for all 580 (and maybe 570?) users:
-H 1 -i 0 -l F16x14 -C 2 x64 exe
Currently hashing at ~320kH/s! My 580 is running @970Mhz core / 2200Mhz mem. Mem speed doesn't affect much if at all, biggest increase is core. So if you can clock higher by lowering your memory, make a mine profile for that and another for normal games if you need the mem speed, usually though core is better there too.

Gumtree, the large international classifieds website and eBay subsidiary, is auto-removing bitcoin-related listings from its UK sites and has said bitcoin falls under its restricted items policy.

User Mark Le from Margate, Kent, reported that when he tried posting requests to buy bitcoins in Gumtree’s ‘Wanted’ section, he received the following message:

What alt coins can I mine with a 1 year old laptop, if any?