Re: [Bitcoin-development] Lets discuss what to do if SHA256d is actually broken

2014-06-05 Thread Rusty Russell
Charlie 'Charles' Shrem csh...@gmail.com writes: Hey Rusty, This is intriguing, do you have a writeup somewhere I can read more about ? OK, ignore the FIXMEs, but I rehashed my stupid sim code, added some graphs to the (clearly unfinished) paper and uploaded it to github:

Re: [Bitcoin-development] Lets discuss what to do if SHA256d is actually broken

2014-06-03 Thread Ethan Heilman
An attack on the mining difficulty algorithm does not imply violation of the typical security properties of a cryptographic hash function*. Assume someone discovers a method which makes it far easier to discover new blocks, this method: may or may not be implementable by the current SHA256 ASIC

Re: [Bitcoin-development] Lets discuss what to do if SHA256d is actually broken

2014-06-03 Thread Kevin
On 6/3/2014 12:29 AM, xor wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Hi, I thought a lot about the worst case scenario of SHA256d being broken in a way which could be abused to A) reduce the work of mining a block by some significant amount B) reduce the work of mining a block

Re: [Bitcoin-development] Lets discuss what to do if SHA256d is actually broken

2014-06-03 Thread Rusty Russell
Luke Dashjr l...@dashjr.org writes: On Tuesday, June 03, 2014 4:29:55 AM xor wrote: Hi, I thought a lot about the worst case scenario of SHA256d being broken in a way which could be abused to A) reduce the work of mining a block by some significant amount B) reduce the work of mining a

Re: [Bitcoin-development] Lets discuss what to do if SHA256d is actually broken

2014-06-03 Thread Charlie 'Charles' Shrem
Hey Rusty, This is intriguing, do you have a writeup somewhere I can read more about ? Thanks, Charlie CharlieShrem.com | *Please **encrypt messages with my PGP key http://charlieshrem.com/contact/* On Tue, Jun 3, 2014 at 8:45 AM, Rusty Russell ru...@rustcorp.com.au wrote: Luke Dashjr

[Bitcoin-development] Lets discuss what to do if SHA256d is actually broken

2014-06-02 Thread xor
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Hi, I thought a lot about the worst case scenario of SHA256d being broken in a way which could be abused to A) reduce the work of mining a block by some significant amount B) reduce the work of mining a block to zero, i.e. allow instant mining.

Re: [Bitcoin-development] Lets discuss what to do if SHA256d is actually broken

2014-06-02 Thread Luke Dashjr
On Tuesday, June 03, 2014 4:29:55 AM xor wrote: Hi, I thought a lot about the worst case scenario of SHA256d being broken in a way which could be abused to A) reduce the work of mining a block by some significant amount B) reduce the work of mining a block to zero, i.e. allow instant