mirror of
https://github.com/bitcoinbook/bitcoinbook
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CH03-04: edits for Murchandamus feedback
- Mention the reason for the long validation time is the verification of transactions. We previously implied it was download time, but some people have really fast internet. - Better describe bitcoind cookie authentication and provide an example to make it even more clear. - Add a link to bitcoin-s - Make the long sidebar on collision attacks even longer by descripting a pre-image attack in addition to the previous descriptions of second pre-image and collision. That way we don't conflate pre-image and second pre-image. - Remove redundant tip box about an oddity in language about compressed and uncompressed private keys. - Link to information about vanity address "mining" (brute forcing)
This commit is contained in:
David A. Harding
parent
67fd4677d1
commit
5b1a5bff0a
@ -47,7 +47,7 @@ differentiate it from other implementations. Bitcoin Core is
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the _reference implementation_ of the Bitcoin system, meaning that it
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provides a reference for how each part of the technology should be
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implemented. Bitcoin Core implements all aspects of Bitcoin, including
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wallets, a transaction and block validation engine, and all modern parts
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wallets, a transaction and block validation engine, tools for block construction, and all modern parts
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of Bitcoin peer-to-peer communication.
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<<bitcoin_core_architecture>> shows the architecture of Bitcoin
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@ -494,12 +494,15 @@ inside the configuration file it refers to.
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datadir:: Select the directory and filesystem in which to put all the
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blockchain data. By default this is the _.bitcoin_ subdirectory of your
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home directory. Make sure this filesystem has several gigabytes of free
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space.
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home directory. Depending on your configuration, this can use from about 10
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gigabytes to almost 1 terabyte as of this writing, with the maximum size
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expected to increase by several hundred gigabytes per year.
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prune:: Reduce the disk space requirements to this many megabytes, by
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prune:: Reduce the blockchain disk space requirements to this many megabytes, by
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deleting old blocks. Use this on a resource-constrained node that can't
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fit the full blockchain.
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fit the full blockchain. Other parts of the system will use other disk
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space that can't currently be pruned, so you will still need at least
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the minimum amount of space mentioned in the +datadir+ option.
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txindex:: Maintain an index of all transactions. This allows you to
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programmatically retrieve any transaction by its ID provided that the
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@ -714,7 +717,7 @@ and their expected output.
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==== Getting Information on Bitcoin Core's Status
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((("Bitcoin Core", "Bitcoin Core API", "status information")))Bitcoin
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Core provides status reports on diffent modules through the JSON-RPC
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Core provides status reports on different modules through the JSON-RPC
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interface. The most important commands include +getblockchaininfo+,
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+getmempoolinfo+, +getnetworkinfo+ and +getwalletinfo+.
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@ -744,9 +747,7 @@ $ bitcoin-cli getnetworkinfo
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"connections_in": 0,
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"connections_out": 10,
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"networks": [
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...
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detailed information about all networks (ipv4, ipv6, onion, i2p, and cjdns)
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...
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"...detailed information about all networks (ipv4, ipv6, onion, i2p, and cjdns)..."
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],
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"relayfee": 0.00001000,
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"incrementalfee": 0.00001000,
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@ -766,9 +767,15 @@ Bitcoin network and the settings related to this node.
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[TIP]
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====
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It will take some time, perhaps more than a day, for +bitcoind+
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to catch up to the current blockchain height as it downloads
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blocks from other Bitcoin nodes. You can check its progress using
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+getblockchaininfo+ to see the number of known blocks.
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to catch up to the current blockchain height as it downloads blocks from
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other Bitcoin nodes and validates every transaction in those
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blocks--almost a billion transactions as of this writng. You can check
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its progress using
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+getblockchaininfo+ to see the number of known blocks. The examples in
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the rest of this chapter assume you're at least at block 775,072.
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Because the security of Bitcoin transactions depends on blocks, some of
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the information in the following examples will change slightly depending
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on how many blocks your node has.
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====
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[[exploring_and_decoding_transactions]]
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@ -1002,9 +1009,22 @@ with the request. Bitcoin Core will create a random password on each
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start and place it in the data directory under the name +.cookie+. The
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+bitcoin-cli+ helper can read this password file given the data
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directory. Similarly, you can copy the password and pass it to curl (or
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any higher level Bitcoin Core RPC wrappers). Alternatively, you can
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any higher level Bitcoin Core RPC wrappers), as seen in <<cookie_auth>>.
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[[cookie_auth]]
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====
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----
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$ cat .bitcoin/.cookie
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__cookie__:17c9b71cef21b893e1a019f4bc071950c7942f49796ed061b274031b17b19cd0
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$ curl --user __cookie__:17c9b71cef21b893e1a019f4bc071950c7942f49796ed061b274031b17b19cd0 --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "getblockchaininfo", "params": [] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/
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{"result":{"chain":"main","blocks":799278,"headers":799278,"bestblockhash":"000000000000000000018387c50988ec705a95d6f765b206b6629971e6978879","difficulty":53911173001054.59,"time":1689703111,"mediantime":1689701260,"verificationprogress":0.9999979206082515,"initialblockdownload":false,"chainwork":"00000000000000000000000000000000000000004f3e111bf32bcb47f9dfad5b","size_on_disk":563894577967,"pruned":false,"warnings":""},"error":null,"id":"curltest"}
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----
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====
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Alternatively, you can
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create a static password with the helper script provided in
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_./share/rpcuser/rpcuser.py_ in Bitcoin Core's source directory.
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_./share/rpcauth/rpcauth.py_ in Bitcoin Core's source directory.
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If you're implementing a JSON-RPC call in your own program, you can use
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a generic HTTP library to construct the call, similar to what is shown
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@ -1013,6 +1033,8 @@ in the preceding +curl+ example.
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However, there are libraries in most popular programming languages that
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"wrap" the Bitcoin Core API in a way that makes this a lot simpler. We
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will use the +python-bitcoinlib+ library to simplify API access.
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This library is not part of the Bitcoin Core project and needs to be
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installed the usual way you install Python libraries.
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Remember, this requires you to have a running Bitcoin Core instance,
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which will be used to make JSON-RPC calls.
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@ -1069,8 +1091,8 @@ a program to run them; you could just as easily use the +bitcoin-cli+
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helper. The next example, however, requires several hundred RPC calls
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and more clearly demonstrates the use of a programmatic interface.
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In <<rpc_block>>, we first retrieve block 277316, then retrieve each of
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the 419 transactions within by reference to each transaction ID. Next,
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In <<rpc_block>>, we first retrieve a block, then retrieve each of
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the transactions within it by reference to each transaction ID. Next,
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we iterate through each of the transaction's outputs and add up the
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value.((("", startref="alicethree")))
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@ -1137,6 +1159,9 @@ https://github.com/btcsuite/btcd[btcd]:: A Go language full-node Bitcoin client
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==== Rust
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https://github.com/rust-bitcoin/rust-bitcoin[rust-bitcoin]:: Rust bitcoin library for serialization, parsing, and API calls
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==== Scala
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https://bitcoin-s.org/[bitcoin-s]:: A Bitcoin implementation in Scala
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==== C#
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https://github.com/MetacoSA/NBitcoin[NBitcoin]:: Comprehensive bitcoin library for the .NET framework
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@ -1,7 +1,7 @@
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[[ch04_keys_addresses]]
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== Keys and Addresses
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Alice wants to pay Bob, but the the thousands of Bitcoin full nodes who
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Alice wants to pay Bob, but the thousands of Bitcoin full nodes who
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will verify her transaction don't know who Alice or Bob are--and we want
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to keep it that way to protect their privacy. Alice needs to
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communicate that Bob should receive some of her bitcoins without tying
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@ -649,7 +649,7 @@ shows the full base58 alphabet.
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====
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To add extra security against typos or transcription errors, base58check
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adds an error-checking code to the base58 alphabet. The checksum is an additional four bytes
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uses the base58 alphabet to also include a _checksum_. The checksum is an additional four bytes
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added to the end of the data that is being encoded. The checksum is
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derived from the hash of the encoded data and can therefore be used to
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detect transcription and typing errors. When presented with
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@ -713,7 +713,7 @@ version prefixes and the resulting base58 characters are shown in
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|=======
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Putting together public keys, hash-based commitments, and base58check
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encocding, we can see the illustration of the conversion of a public key
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encoding, we can see the illustration of the conversion of a public key
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into a Bitcoin address in <<pubkey_to_address>>.
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[[pubkey_to_address]]
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@ -739,7 +739,8 @@ wrapper
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}
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----
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The result contains the key as payload, the WIF version prefix 128, and a checksum.
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The result contains the key as payload, the WIF version prefix 128 (0x80
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in hex), and a checksum.
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Notice that the "payload" of the compressed key is appended with the
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suffix +01+, signaling that the derived public key is to be compressed:
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@ -840,6 +841,7 @@ key can produce a public key expressed in two different formats
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addresses. However, the private key is identical for both Bitcoin
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addresses.
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//FIXME:misaligned text, see Murch CH04 feedback
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[[pubkey_compression]]
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[role="smallerseventy"]
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.Public key compression
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@ -864,7 +866,7 @@ compressed public keys.
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[[addresses_for_p2sh]]
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=== Legacy Pay-to-Script-Hash (P2SH)
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As we've seen in preceding sections, someone receiving Bitcoins (like
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As we've seen in preceding sections, someone receiving bitcoins (like
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Bob) can require payments to him contain certain constraints in their
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output script. Bob will need to fulfill those constraints using an
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input script when he spends those bitcoins. In <<p2pk>>, the constraint
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@ -883,7 +885,7 @@ for which she needs to pay transaction fees every time she wants to spend
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money to Bob. However, the solution of using hash functions to create
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small commitments to large amounts of data also applies here.
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The BIP16 upgrade to the Bitcoin protocol in 2013 allows an
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The BIP16 upgrade to the Bitcoin protocol in 2012 allows an
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output script to commit to a _redemption script_ (_redeem script_). When
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Bob spends his bitcoins, his input script need to provide a redeem script
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that matches the commitment and also any data necessary to satisfy the
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@ -959,22 +961,28 @@ transactions.
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====
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P2PKH and P2SH are the only two script templates used with base58check
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encoding. They are now known as legacy addresses and, as of early 2023,
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are only used in
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https://transactionfee.info/charts/payments-spending-segwit/[about 10% of transactions].
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encoding. They are now known as legacy addresses and have become less
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common over time.
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Legacy addresses were supplanted by the bech32 family of addresses.
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[[p2sh_collision_attacks]]
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.P2SH collision attacks
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****
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All addresses based on hash functions are theoretically vulnerable to an
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attacker finding two different inputs (e.g. redeem scripts) that produce
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the same hash function output (commitment). For addresses created
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attacker independently finding the same input that produced the hash
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function output (commitment). In the case of Bitcoin, if they find the
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input the same way the original user did, they'll know the user's private
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key and be able to spend that user's bitcoin. The chance of an attacker
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independently generating the input for an existing commitment is
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proportional to the strength of the hash algorithm. For a secure
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160-bit algorithm like HASH160, the probability is 1-in-2^160^. This is
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a _pre-image attack_.
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An attacker can also try to generate two different inputs (e.g. redeem
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scripts) that produce the same commitment. For addresses created
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entirely by a single party, the chance of an attacker generating a
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different input for an existing commitment is proportional to the
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strength of the hash algorithm. For a secure 160-bit algorithm like
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HASH160, the probability is 1-in-2^160^. This is a _second pre-image
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attack_.
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different input for an existing commitment is also about 1-in-2^160^ for
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the HASH160 algoritm. This is a _second pre-image attack_.
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However, this changes when an attacker is able to influence the original input
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value. For example, an attacker participates in the creation of a
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@ -1007,7 +1015,7 @@ special knowledge on the part of wallet developers is to simply use
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a stronger hash function. Later upgrades to Bitcoin made that possible
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and newer Bitcoin addresses provide at least 128 bits of collision
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resistance. To perform 2^128^ hash operations would require all current
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Bitcoin miners about 50 billion years to perform.
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Bitcoin miners about 32 billion years to perform.
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Although we do not believe there is any immediate threat to anyone
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creating new P2SH addresses, we recommend all new wallets use newer
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@ -1016,19 +1024,19 @@ types of addresses to eliminate address collision attacks as a concern.
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=== Bech32 addresses
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In 2017, the Bitcoin protocol was upgraded to prevent transaction
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In 2017, the Bitcoin protocol was upgraded. When the upgrade is used,
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it prevents transaction
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identifiers (txids) from being changed without the consent of a spending
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user (or a quorum of signers when multiple signatures are required).
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The upgrade, called _segregated witness_ (or _segwit_ for short), also
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provided additional capacity for transaction data in blocks and several
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other benefits. However, users wanting direct access to segwit's
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benefits had to accept payments to variations on the legacy P2PKH and
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P2SH scripts.
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benefits had to accept payments to new output scripts.
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As mentioned in <<p2sh>>, one of the advantages of the P2SH output type
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was that a spender (such as Alice) didn't need to know the details of
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the script the receiver (such as Bob) used. The segwit upgrade was
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designed to be compatible with this mechanism, allowing users to
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designed to use this mechanism, allowing users to
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immediately begin accessing many of the new benefits by using a P2SH
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address. But for Bob to gain access to all of the benefits, he would
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need Alice's wallet to pay him using a different type of script. That
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@ -1057,8 +1065,8 @@ identified several problems with base58check:
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located. It might take you several frustrating minutes to eventually
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discover the mistake.
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- A mixed case alphabet also requires extra space to encode in QR code
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images, which are commonly used to share addresses and invoices
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- A mixed case alphabet also requires extra space to encode in QR codes,
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which are commonly used to share addresses and invoices
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between wallets. That extra space means QR codes need to be larger at
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the same resolution or they become harder to scan quickly.
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@ -1078,8 +1086,9 @@ The "32" stands for the number of characters in the bech32 alphabet
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- Bech32 uses only numbers and a single case of letters (preferably
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rendered in lowercase). Despite its alphabet being almost half the
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size of the base58check alphabet, bech32 addresses are only slightly
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longer than the longest equivalent P2PKH legacy addresses.
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size of the base58check alphabet, a bech32 address for a P2WPKH script
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is only slightly longer than a legacy address for an equivalent P2PKH
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script.
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- Bech32 can both detect and help correct errors. In an address of an
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expected length, it is mathematically guaranteed to detect any error
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@ -1109,8 +1118,8 @@ https://bitcoin.sipa.be/bech32/demo/demo.html[bech32 address decoder demo].
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<<bech32_qrcode_uc_lc>>.
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[[bech32_qrcode_uc_lc]]
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.The same bech32 address QR encoded in uppercase and lowercase
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image::images/bech32-qrcode-uc-lc.png["The same bech32 address QR encoded in uppercase and lowercase"]
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.The same bech32 address QR encoded in lowercase and uppercase
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image::images/bech32-qrcode-uc-lc.png["The same bech32 address QR encoded in lowercase and uppercase"]
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- Bech32 takes advantage of an upgrade mechanism designed as part of
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segwit to make it possible for spender wallets to be able to pay
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@ -1547,16 +1556,6 @@ key. The resulting base58check-encoded private key is called a
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starting with "5" as is the case with WIF-encoded (uncompressed) keys
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from older wallets.
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[TIP]
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====
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"Compressed private keys" is a misnomer! They are not compressed;
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rather, WIF-compressed signifies that the keys should only be used to
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derive compressed public keys and their corresponding Bitcoin addresses.
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Ironically, a "WIF-compressed" encoded private key is one byte longer
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because it has the added +01+ suffix to distinguish it from an
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"uncompressed" one.((("", startref="KAaddress04")))
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====
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=== Advanced Keys and Addresses
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((("keys and addresses", "advanced forms", id="KAadvanced04")))In the
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@ -1587,7 +1586,7 @@ Elliptic Curve Cryptography (ECC) and SHA as any other address. You can
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no more easily find the private key of an address starting with a vanity
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pattern than you can any other address.
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In <<ch01_intro_what_is_bitcoin>>, we introduced Eugenia, a children's
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Eugenia is a children's
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charity director operating in the Philippines. Let's say that Eugenia is
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organizing a bitcoin fundraising drive and wants to use a vanity Bitcoin
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address to publicize the fundraising. Eugenia will create a vanity
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@ -1650,8 +1649,8 @@ Vanity searches on GPU systems are many orders of magnitude
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faster than on a general-purpose CPU.
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Another way to find a vanity address is to outsource the work to a pool
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of vanity miners. A pool is a service that
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allows those with GPU hardware to earn bitcoin searching for vanity
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of vanity miners. A https://bitcointalk.org/index.php?topic=84569.0[vanity pool] is a service that
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allows those with fast hardware to earn bitcoin searching for vanity
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addresses for others. For a fee, Eugenia can outsource the search for a
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seven-character pattern vanity address and get results in a few hours
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instead of having to run a CPU search for months.
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@ -1687,8 +1686,8 @@ gives discount pricing to Eugenia.
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// https://github.com/MakisChristou/vanitybech
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Given those problems, we don't expect to see many vanity addresses in
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the future, although there will probably always be some.
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We don't expect to see many vanity addresses in
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the future unless the above problems are solved.
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[[paper_wallets]]
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==== Paper Wallets
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@ -3,9 +3,9 @@ from bitcoin.rpc import RawProxy
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p = RawProxy()
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# The block height where Alice's transaction was recorded
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blockheight = 277316
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blockheight = 775072
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# Get the block hash of block with height 277316
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# Get the block hash of the block at the given height
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blockhash = p.getblockhash(blockheight)
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# Retrieve the block by its hash
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Loading…
Reference in New Issue
Block a user