Don't scrape the HTML pages. There are better API pages:
http://blockexplorer.com/q/getreceivedbyaddress
http://blockexplorer.com/q/mytransactions

The way you cancel it is by sending a locked transaction using the same coins. Then your other transaction becomes invalid.

If the merchant is malicious, you would want to cancel the transaction a few days before it becomes locked. Otherwise they have a chance of getting their version in a block before your version.

You can change anything if you own all of the inputs. You can even reverse it. Miners can tell because the inputs of the new transaction all have higher sequence numbers than the old ones.

With the non-default SIGHASH modes, multiple people can contribute inputs into a transaction. Then you can only change certain things, depending on the mode.

They are the same. getblocknumber is obsolete.

It used to be that getblocknumber would return the highest block number, while getblockcount would return the total number of blocks. Confusingly, this behavior was switched when getblocknumber was made obsolete, so getblockcount now actually gives the highest block number.

The total number of blocks is different from the highest block number because the genesis block is block #0.

Thanks a lot for all the offers! I will consider them all tomorrow.


I would prefer that someone else maintain it, though I can do it.

I won't accept physical machines sent to me, as one of the main things this is meant to solve is situations when my power or Internet is offline.


ABE has reduced functionality.


I'll probably need more than 2GB in the long-term.


I will consider this if load becomes the main problem, but I'm really trying to solve downtime right now. This request was prompted by the fact that my Internet access will be down for a day or two in the near future.

To get the performance that BBE currently has (which is not perfect), I give PostgreSQL almost my entire 3 GB of memory. Linode charges $160/month for 4GB. Less memory will equal less performance unless disk speed is much better (which I doubt will be the case with any VPS).

They don't have to store it. The network will forget about your 0-confirmation transactions after a few days if you don't rebroadcast them.

Yes, it's lock_time. Each input's "sequence" is also related to this.

There are many features that are not exposed. Check out:
https://en.bitcoin.it/wiki/Contracts
https://en.bitcoin.it/wiki/Script

Edit: I no longer need a mirror.

I need someone to run a permanent mirror of blockexplorer.com. I will switch to the mirror while doing maintenance, and I will share load with it in times of heavy load.

You will need to agree to these terms:
- Your mirror will only be accessible via IP address when it is not blockexplorer.com
- Your mirror will be excluded with robots.txt when it is not blockexplorer.com
- You may not allow the code to be released
- You may not base any software off of my code
- You may not automatically publish any data gotten from the BBE database

You can, however, use the local BBE database to gather information that you use privately or manually publish. You can publish the IP address for times when BBE is unexpectedly down.

Requirements:
- PostgreSQL
- PHP with sockets and bcmath
- Some web server able to alias all requests to one file (I use Apache)
- The ability to compile Bitcoin with my modified version of getblock

Typical load is about 800,000 requests per day, with a burst of perhaps 1.5 million requests per day. Most of these are quite small, however. Average upload is 60 KB/s. My server has a Pentium D 3.4GHz CPU with 3GB of memory, and it's doing alright for now.

You must be extremely trustworthy, as I will share the HTTPS private key.

PM me if you are interested.

The Bitcoin node at 99.27.237.13 is permanently moving to a different IP address in about a week. This node was in the first set of seednodes and the first version of the "fallback nodes" page, and it is blockexplorer.com. It is possible that you are connecting to it with -addnode. Please check your configuration and remove this IP if it exists.

Added.

It would be better to have a separate watchlist system in addition to "new replies to your posts". Why should you be able to break the page's stated function of showing new replies to your posts?

I tried to install it once, but it caused problems and I didn't want to deal with it at the time. Maybe I'll try again later.

Post it in this section.

You could send transactions with an nLockTime equal to the subscription due date. (nLockTime is an already-existing feature that prohibits a transaction from being accepted into a block until a certain time.) Send this transaction to the service a month ahead of time, and then you don't need to be online at the payment time. You can cancel it at any time.

You've reported no posts. If you want something to be done about a post, you must report it.

If the services kept each person's BTC separate, they could give people withdrawal transactions in advance. The users could then withdraw at any time without contacting the service by broadcasting the transaction. The users would also know immediately if any of these funds were spent.

I might use it if it had extremely good physical security. Like CyberBunker, but devoted to the bank. Physical security is the only thing I can't do -- I have encryption and backups handled.

I've been thinking recently about the interesting security measures such a bank could use. It'd be really fun to build it.

The target is stored in a fixed-size form that basically says, "This many zeroes followed by these bytes, followed by enough zeroes to fill 256 bits". It can handle any number, with lower precision for higher numbers.

"Difficulty" isn't used for anything except display, so it doesn't matter how that is stored.

HTTPS prevents someone who is sitting between you and the destination on the network from reading or modifying your transmissions. For example, it prevents your ISP from seeing your MtGox password. Usually, anyone between you and the destination is pretty trustworthy, but this is not the case if you live in a non-free country or if you are using a free proxy like Tor.

This compromise means that all HTTPS connections are suspect until things are sorted out. Even sites that don't use StartSSL can have their HTTPS broken. Even if MtGox was using Verisign, they would be affected equally.

I recommend installing the Certificate Patrol and Perspectives extensions for Firefox:
http://patrol.psyced.org/
http://www.networknotary.org/firefox.html

Certificate Patrol warns you whenever a site's certificate changes. This will happen when an attacker tries to exploit a compromised certificate authority like StartSSL. It also happens occasionally for other reasons.

Perspectives asks several notary servers for information about certificates. If the notaries see a different certificate than you do, then there is probably an attack going on. In the settings, use these options:
- Percentage of notaries...: 100
- Days of continuous...: 0
- Contact notaries for all HTTPS sites: yes
- Allow Perspectives to automatically...: no (unless you want to allow Perspectives to stand in for a CA when a site is using a self-signed certificate)