How get raw block data? - Bitcoin Stack Exchange

Getblock Nodes. Free access to blockchain nodes

Hello!
We are a multi-block explorer, and we have several blockchain nodes:
In the near future we are expecting the addition :)
If you are interested in getting a free access to blockchains API (JSON-RPC), simply follow the link (Feedback form at the bottom of the page).
Tell us about your project or why you need access to blockchain data, and we will grant you a free API key.
Since as a result we become partners, and all serious partnerships are public, we will have to exchange active links in the «Partners» section on our websites.
submitted by getblockio to u/getblockio [link] [comments]

PIVX Core Wallet 3.0.5 final release (November 13th, 2017) - Mandatory Upgrade

Github release link
Forum Post

Important Notes

Upgrade instructions

1- Download the appropriate release for your platform from the Github release link. For command line installs/updates this link may help.
2- Start up your client and see if you are on the wrong chain by using this link (Am I forked?) or manually comparing your latest block hash against the [block explorer](www.presstab.pw/phpexplorePIVX/index.php#)
3- If you are on the correct chain, let it fully sync (or as far as it will go) and then repeat step 2. If you are still on the right chain move on to step 4. If you're on the wrong chain, download the chainstate from this link (mirror) and follow the instructions to install it. Do NOT delete wallet.dat or your backups folder. Once this is done, restart your client and let it finish syncing
  1. stop your wallet and/or daemon
  2. locate the folder with the blockchain folders (usually ~/.pivx/)
  3. do a complete(!) backup of this folder in case something goes wrong
  4. completely remove the folders "blocks", "chainstate", "sporks" and "zerocoin"
  5. download one of the snapshot-files (preferably the newest one) above into this folder
  6. unpack the snapshot file: 'unzip '
  7. the folders deleted above are now replaced by the ones from the snapshot
  8. restart your wallet and/or daemon
4- On this step you should be fully synced and on the right chain. Using the debug screen or pivx-cli, use the command
spork show 
to output your spork status. Have a look at spork 16 and make sure the value is 1510179528 (now 1609459199). If it is, go ahead and start staking.
If you are having trouble getting the correct value for spork 16, try adding nodes to your pivx.conf file that are protocol 70912. A list of 70912 nodes can be found at http://www.presstab.pw/phpexplorePIVX/nodes.php . This can be done from the debug menu or with pivx-cli by saying
addnode 123.45.67.89 add 

Notable Changes

libzerocoin Exploit Fix

zPIV relies on a 3rd party library called libzerocoin. All currencies that utilize the zerocoin protocol use libzerocoin, and many of those currencies have been exposed to an exploit which allowed for the creation of multiple zero-knowledge spending proofs for one single zerocoin mint. The PIVX developers were able properly identify the exploit, track down any fraudulent spending proofs, link the fraudulent spending proofs with their one valid proof that they were mutated from, and remove any mints from the accumulators that were derived from the invalid spends.

zPIV Maintenance Mode Spork

Handling the above noted libzerocoin exploit required the PIVX team to immediately release a patched wallet to as many users as possible which rejected bad spends and also disabled all zPIV transactions in general. The process of releasing a patched wallet in such a small time frame is frustrating and difficult for all members of the PIVX team and especially users of PIVX. The PIVX developers have added a new spork which allows for zPIV transacting to be turned on/off without having to release a patched wallet. This will allow much smoother operation if any problems occur in the future, and should also allow exchanges and 3rd party services to continue to operate even if zPIV is in maintenance mode.

Accumulator Code Refactor

The zPIV accumulator code has undergone a major refactor. Accumulators are one of the most essential components of the zerocoin protocol, and also one of the most computationally expensive parts of the protocol. This refactoring speeds up syncing and spending of zPIV by over 5x. The new code also allows for spending of zPIV with only 2 required mints occurring on the network after your mint has been added, whereas before 3 were required. This refactor allows for lighter resource load and a smoother user experience.

Money Supply Indexing

The exploit in libzerocoin threw off some of the wallet's internal money supply calculations for both the zPIV supply and the PIV supply. User's wallet's will automatically recalculate the supply on block 908001. User's also have the ability to recalculate supply using the startup flag reindexmoneysupply.

More Extensive Tracking of zPIV Supply Through RPC

More information has been added to the getinfo and getblock RPC calls, which now display the total zPIV supply as well as the balance for each zPIV accumulator.

Multisig GUI

Provides functionality which is currently only available through raw transactions. Multisignature addresses require signatures from multiple parties before coins belonging to the address are spent. Accessed through the File dropdown menu.

Credits

FAQ

  • Will I lose piv or zpiv?
    • No. Backup your wallet.dat again for good measure and never delete a wallet.dat file.
  • My wallet is stuck on block ?
    • Check if you're forked (Am I forked?) and then check if you're really on v3.0.5. If you're on the right version and chain, just hang tight and your wallet will find a good node to sync with eventually. Contact support if it's more than a few hours and the problem persists
  • My zPIV balance is incorrect
    • Contact support in discord or via the Support Portal. Please note that during the upgrade period and zerocoin maintenance mode there may be delays.
submitted by turtleflax to pivx [link] [comments]

[Informational] [CC0] Plug In To The Bitcoin Network

Bitcoin Peer to Peer Network Protocol

The Bitcoin network is designed to operate in a peer to peer configuration, in a reflection of the overall decentralized design of the system. The network goal is to sync the Blockchain, the transaction record and payment settlement system through which Bitcoins are minted and exchanged with Bitcoin users. A high level view of the network is that of a wide array of individual peers, each helping to broadcast updated Blockchain information across the entire group.
The broadcast sync of the Blockchain and the network setup and operational action are accomplished through a narrow network protocol, consisting of a small set of messages. Most messages are designed with pushing data in mind, to continue to propagate waves of updated Blockchain and peer data to local peers and across the greater network.

Connecting

All Bitcoin network communication occurs using TCP, the standard Internet protocol for reliable networking. Bitcoin has supported the IPv6 standard since September of 2012, and can be used over a user selected port, with the default being 8333.
When a Bitcoin node is instantiated for the first time, it needs to find a way to connect to the greater network. At the start of the project, new nodes would automatically connect to a hard-coded IRC server, with IRC channels being used to publish and discover IP addresses of network nodes. This bootstrapping process was created in 2011, complementing the IRC system it would ultimately wholly replace. In this system hard-coded DNS address based seeds are resolved to the IP addresses of seed nodes to direct a new node onto the network. Since 2012 Bitcoin Core developers Luke-Jr and Pieter Wuille have operated seed nodes, along with various others over the years.
When connecting to a node IP, a Bitcoin node will send its version as the initial message, in a handshaking process where information about its makeup including its current clock value is published to the remote node. The specific messages used are version, which sends the node information, and verack, which acknowledges the receipt of the version information. This handshake helps a node define a normalized network clock value: time calculations a node makes are based not off of its own clock, but rather the median time from all successfully connected peers.
After the initial bootstrapped connection onto the network, previously connected-to peers as well as relayed known local active peer information is cached. Nodes are designed to recall other nodes in an archival list. This list of node IPs is cached in order to bypass the node seed stage on subsequent starts. On each network join, a node will consult its cache of nodes, semi-randomly selecting nodes to attempt to connect to, with a prioritization of most recently active.

Syncing

Once nodes have successfully joined the network, they are then faced with their primary task of syncing the Blockchain. The workhorse message that helps a node accomplish this task is the inventory or more precisely inv message, which a node uses to push listings of blocks and transactions to connected peers. Inventory messages are simply concise high level identification information, they do not carry any information beyond a listing of blocks and transactions. These messages are published constantly, as novel blocks and transactions are validated and then pushed to other peers to relay the new information.
Specific inventory messages may be requested directly from a connected peer using the getblocks message that queries about a specific set of blocks. This message is used to sync nodes that are out of date, such as nodes that are new to the network and must sync the entire blockchain through a long series of getblocks requests.
When an inventory message is received, listed inventory of blocks and transactions may be requested through the getdata request. This is generally performed when a node receives an inventory message containing novel block or transaction information. In response to the getdata response the node returns with a block or tx message, sending blocks and transactions respectively.

Syncing to Light Clients

Full nodes may also service the syncing needs of light clients, which some call SPV clients after a general proposal made by Satoshi in the original Bitcoin whitepaper. These clients avoid validating the blockchain to provide a more practical user experience at the cost of incurring counter-party risk of an abusive miner or set of miners.
Filter message features so that full node could service requests for light clients were added through BIP 37. Light clients uses the getheaders message to request that full nodes return Blockchain headers information which are sent using the headers message. The chain of Blockchain headers are used to piece together the chain with the greatest proof of work. This is used to verify transactions as being on the longest chain of blocks, with the important caveat that it may be an invalid chain.
Light clients also use bloom messages to request transactions that they care about, they do not ask directly for transactions in an effort to add some slight privacy to the client's financial status, however these efforts have only a small impact and are not comprehensive.

Peer Announcements

In addition to syncing the Blockchain, the Bitcoin network syncs information about the IP addresses that comprise the network, to provide for sustainable connectivity. Nodes publish to other nodes the set of active peers they know about using the addr message, which can contain a list of up to a thousand known active nodes. Nodes can also ask other nodes for an addr message using a getaddr message. Every twenty four hours every node will broadcast a heartbeat addr message, which is passed along to two connected nodes.
General network connectivity may also be tested by a node using the ping message, which does nothing other than attempt a connection to verify connectivity.

Obsolete Messages

In the original Bitcoin protocol, support was present for an IP based sending system. The concept allowed connecting to a node directly to make a transaction. To accomplish that task nodes used messages that were later deprecated and removed. IP based sending was eliminated very early on due to security, privacy, and practicality issues.
Although the Bitcoin network was designed as a group of headless automatons, early in its life various critical defects were found that required aggressive central action to remedy. As a practical solution to facilitate the rapid deployment of requisite fixes, Satoshi Nakamoto devised an alerting system for sending version update messages across the node network.
This system used a protocol message called alert to directly broadcast a signed message from Satoshi, to be shown to users to inform them of critical information. To avoid a singular dependency Satoshi shared the signing key with others, which over time became an unnecessary risk to the network. In April of 2016 the release of Bitcoin Core version 0.12.1 eliminated the alert system.
submitted by pb1x to writingforbitcoin [link] [comments]

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