Cryptography
45 writings, oldest first
- Private email (Adam Back)
Citation of your Hashcash paper
I'm getting ready to release a paper that references your Hashcash paper and I wanted to make sure I have the citation right. Here's what I have: [5] A. Back, "Hashcash - a denial of service counter-measure,"…
- Private email (Adam Back)
RE: Citation of your Hashcash paper
Thanks, I wasn't aware of the b-money page, but my ideas start from exactly that point. I'll e-mail him to confirm the year of publication so I can credit him. The main thing my system adds is to also use proof-of-work to support a…
- Private email (Wei Dai)
Citation of your b-money page
I was very interested to read your b-money page. I'm getting ready to release a paper that expands on your ideas into a complete working system. Adam Back (hashcash.org) noticed the similarities and pointed me to your site. I need to find…
- bitcoin.org
Bitcoin: A Peer-to-Peer Electronic Cash System
Bitcoin: A Peer-to-Peer Electronic Cash System Satoshi Nakamoto satoshin@gmx.com www.bitcoin.org Abstract. A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without…
- Cryptography mailing list (metzdowd)
Bitcoin P2P e-cash paper
I've been working on a new electronic cash system that's fully peer-to-peer, with no trusted third party. The paper is available at: http://www.bitcoin.org/bitcoin.pdf The main properties: Double-spending is prevented with a peer-to-peer…
- Cryptography mailing list (metzdowd)
Bitcoin P2P e-cash paper
I'll try and hurry up and release the sourcecode as soon as possible to serve as a reference to help clear up all these implementation questions. Ray Dillinger (Bear) wrote: Only the buyer signs, and there's no blinding. Identities are…
- Cryptography mailing list (metzdowd)
Bitcoin P2P e-cash paper
Ray Dillinger wrote: Right, it's ECC digital signatures. A new key pair is used for every transaction. It's not pseudonymous in the sense of nyms identifying people, but it is at least a little pseudonymous in that the next action on a…
- Private email (Hal Finney)
Re: Crash in bitcoin 0.1.0
OK, thanks. The one in bitcoin-0.1.1-exe-dbg.rar is the same build as in bitcoin-0.1.1.rar. I forgot, when you build debug on MSVC, it uses the debug versions of the runtime DLLs, which aren't included with Windows distributions.…
- Private email (Dustin Trammell)
Re: Bitcoin v0.1 released
Sweet, I was looking for a group like that on Usenet at one point to see what I would use if I needed, and nothing really fit. I'm sure Google groups is a lot easier to post to. There are some scenarios where a Usenet or Google group…
- P2P Foundation forum
Bitcoin open source implementation of P2P currency
I've developed a new open source P2P e-cash system called Bitcoin. It's completely decentralized, with no central server or trusted parties, because everything is based on crypto proof instead of trust. Give it a try, or take a look at…
- P2P Foundation p2p-research list
[p2p-research] Bitcoin open source implementation of P2P currency
I've developed a new open source P2P e-cash system called Bitcoin. It's completely decentralized, with no central server or trusted parties, because everything is based on crypto proof instead of trust. Give it a try, or take a look at…
- P2P Foundation p2p-research list
[p2p-research] Bitcoin open source implementation of P2P currency
Martien van Steenbergen wrote: </i>><i> His concept makes sure money is anonymous unless it is compromised, i.e. </i>><i> the same money spent more than once. As soon as it's compromised, the </i>><i> ‘counterfeiter’ is immediately…
- bitcoin-list (SourceForge)
Re: [bitcoin-list] Bitcoin v0.1.5 released
Hal Finney wrote: The current version will work fine. They'll each connect over the Internet, while incoming connections only come to the host that port 8333 is routed to. As an optimisation, I'll make a switch "-connect=1.2.3.4" to make…
- Private email (Martti Malmi)
Re: Bitcoin
mmalmi@cc.hut.fi wrote: That would be great! I added you (dmp1ce) as a dev to the sourceforge project and gave you access to edit the web space and everything. Definitely. This will be an absolutely essential feature once things get…
- Private email (Martti Malmi)
Re: Linux build ready for testing
You really don't want to keep running in Wine, you're getting database errors (db.log). You probably developed these rituals of transferring to a fresh install to cope with database corruption. If there is a way to lose unconfirmed…
- BitcoinTalk
Re: 64bit support
I haven't tried compiling 64-bit yet. 64-bit wouldn't make it any faster, since it uses 64-bit numbers in only a few places and SHA-256 is a 32-bit algorithm, but it may be convenient for those running a 64-bit OS. If I get a chance I'll…
- BitcoinTalk
Re: A newb's test - anyone want to buy a picture for $1?
Yes, it's a technical limitation. Sending by bitcoin address enters the transaction into the network and the recipient discovers it from the network. You don't connect directly with them and they don't have to be online at the time. I…
- BitcoinTalk
Re: A newb's test - anyone want to buy a picture for $1?
The recommended ways to do a payment for an order: 1) The merchant has a static IP, the customer sends to it with a comment. 2) The merchant creates a new bitcoin address, gives it to the customer, the customer sends to that address. This…
- BitcoinTalk
Proof-of-work difficulty increasing
We had our first automatic adjustment of the proof-of-work difficulty on 30 Dec 2009. The minimum difficulty is 32 zero bits, so even if only one person was running a node, the difficulty doesn't get any easier than that. For most of last…
- BitcoinTalk
Re: Dealing with SHA-256 Collisions
SHA-256 is very strong. It's not like the incremental step from MD5 to SHA1. It can last several decades unless there's some massive breakthrough attack. If SHA-256 became completely broken, I think we could come to some agreement about…
- BitcoinTalk
Re: 0.3 almost ready
I don't know. Maybe someone with more Linux experience knows how to install the library it needs. I built it on Ubuntu 10.04. I hope that wasn't a mistake. Maybe it should have been built on an older version for more backward…
- BitcoinTalk
Re: Hash() function not secure
SHA256 is not like the step from 128 bit to 160 bit. To use an analogy, it's more like the step from 32-bit to 64-bit address space. We quickly ran out of address space with 16-bit computers, we ran out of address space with 32-bit…
- BitcoinTalk
Re: MSVC build & SHA-256
OpenSSL doesn't have any interface for doing just the low level raw block hash part of SHA256. SHA256 begins by wrapping your data in a specially formatted buffer. Setting up the buffer takes an order of magnitude longer than the actual…
- BitcoinTalk
Re: Stealing Coins
Red, thanks for telling me privately first! Please go ahead and post it (and relieve the suspense for everyone!) His point is that transactions paid to a Bitcoin Address are only as secure as the hash function. To make Bitcoin Addresses…
- BitcoinTalk
Re: Stealing Coins
2^80 is if you can use a birthday attack. You can't use a birthday attack for this, so the difficulty is the full 2^160 bits. Although, if you were trying to crack any one of 1 million (2^20) transactions, you could do a partial birthday…
- BitcoinTalk
Re: Stealing Coins
Sorry, actually it's ECDSA (Elliptic Curve Digital Signature Algorithm) not RSA. I shouldn't have said "prime numbers". ECDSA doesn't take much time to generate a keypair.
- BitcoinTalk
Re: Bitcoin x86 for Windows
I added the cached SHA256 state idea to the SVN, rev 113. The speedup is about 70%. I credited it to tcatm based on your post in the x64 thread. I can compile the Crypto++ 5.6.0 ASM SHA code with MinGW but as soon as it runs it crashes.…
- BitcoinTalk
Re: Bitcoin x86 for Windows
I added a subset of the Crypto++ 5.6.0 library to the SVN. I stripped it down to just SHA and 11 general dependency files. There shouldn't be any other crypto in there other than SHA. I aligned the data fields and it worked. The ASM…
- BitcoinTalk
Re: Build error SVN r115 on my Mac: workaround
Was that the only thing I broke in the OSX build?! Does it actually work after just that one change? I had to do that for makefile.vc also. It compiled, but SHA-256 didn't work correctly; it returned the same incorrect hash each time.…
- BitcoinTalk
*** ALERT *** Upgrade to 0.3.6
Please upgrade to 0.3.6 ASAP! We fixed an implementation bug where it was possible that bogus transactions could be displayed as accepted. Do not accept Bitcoin transactions as payment until you upgrade to version 0.3.6! If you can't…
- BitcoinTalk
Please upgrade to 0.3.8!
Version 0.3.8 adds an important security improvement. Everyone should upgrade to get this change. The new safety feature displays a warning message in the status bar and locks down RPC if it detects a problem that may require an upgrade.…
- BitcoinTalk
Version 0.3.8.1 update for Linux 64-bit
When we switched to Crypto++ 5.6.0 SHA-256 in version 0.3.6, generation got broken on the Linux 64-bit build. Version 0.3.8.1 is on SourceForge with the 64-bit binary updated. Download:…
- BitcoinTalk
Re: 4 hashes parallel on SSE2 CPUs for 0.3.6
MinGW on Windows has trouble compiling it: g++ -c -mthreads -O2 -w -Wno-invalid-offsetof -Wformat -g -D__WXDEBUG__ -DWIN32 -D__WXMSW__ -D_WINDOWS -DNOPCH -I"/boost" -I"/db/build_unix" -I"/openssl/include" -I"/wxwidgets/lib/gcc_lib/mswud"…
- BitcoinTalk
tcatm's 4-way SSE2 for Linux 32/64-bit is in 0.3.10
0.3.10 has tcatm's 4-way SSE2 as an option switch. Use the switch "-4way" to turn it on. Without the switch you get Crypto++ ASM SHA-256. I could only get this working with Linux. Download: Get 0.3.10 from…
- BitcoinTalk
Re: overflow bug SERIOUS
Don't update the block chain download. When you take someone's block chain download, you don't want it right up to the end. A somewhat old one is better so it can download and verify the most recent blocks. tcatm's 4-way SSE2 SHA-256 is…
- BitcoinTalk
Re: overflow bug SERIOUS
Starting at 67000 is perfect. Yeah, at the moment you'll stop at 74638. It should start slowly creeping up as more nodes upgrade and generate. Linux build links below. The Linux version includes tcatm's 4-way SSE2 SHA-256 that makes…
- BitcoinTalk
Version 0.3.10 - block 74638 overflow PATCH!
Version 0.3.10 patches the block 74638 overflow bug. http://bitcointalk.org/index.php?topic=823 The Linux version includes tcatm's 4-way SSE2 SHA-256 that makes generating faster on i5, i7 (with hyperthreading) and AMD CPU's. Try the…
- BitcoinTalk
Re: tcatm's 4-way SSE2 for Linux 32/64-bit 0.3.9 rc2
GCC 4.3.3 doesn't support -march=amdfamk10. I get: sha256.cpp:1: error: bad value (amdfamk10) for -march= switch Hey, you may be onto something! hyperthreading didn't help before because all the work was in the arithmetic and logic units,…
- BitcoinTalk
Re: tcatm's 4-way SSE2 for Linux 32/64-bit is in 0.3.10
I wrapped sha256.cpp in #ifdef FOURWAYSSE2 #endif // FOURWAYSSE2 try it now.
- BitcoinTalk
Re: Difficulty: More nodes active, or faster nodes?
The performance numbers posted from a VIA C7's hardware SHA-256 weren't astronomical. Only in the 1500 khash/s range. If you think about it, just because it's implemented in hardware doesn't mean it's crazy fast. It still has to do all…
- BitcoinTalk
Re: Message Encryption as a built-in feature?
Theymos already said this... ECDSA does not support encrypting messages. Only digital signatures.
- BitcoinTalk
Re: Suggestion: Allow short messages to be sent together with bitcoins ?
ECDSA can't encrypt messages, only sign signatures. It would be unwise to have permanently recorded plaintext messages for everyone to see. It would be an accident waiting to happen. If there's going to be a message system, it should be a…
- BitcoinTalk
Re: New demonstration CPU miner available
You should try it with tcatm's 4-way SSE2 SHA in sha256.cpp. It compiles fine as a C file, just rename sha256.cpp to sha256.c. I was able to get it to work in simple tests on Windows, but not when linked in with Bitcoin. It may have a…
- BitcoinTalk
Re: BitDNS and Generalizing Bitcoin
The incentive is to get the rewards from the extra side chains also for the same work. While you are generating bitcoins, why not also get free domain names for the same work? If you currently generate 50 BTC per week, now you could get…
- Private email (Mike Hearn)
More BitCoin questions
By the way, if you didn't see it already, there's a discussion on the security of secp256k1 on the forum: http://www.bitcoin.org/smf/ind ex.php?topic=2699.0 Hal (i presume this is Hal Finney) Yes, it's him. He was supportive on the…
