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42 coin chart, buy 42 coin

42-coin is extremely rare cryptocurrency with unique deflationary emission model, fair distribution (no ICO, premine or instamine) and both private and public transaction support. It is based on an open source peer-to-peer internet protocol and hybrid Proof-of-Work / Proof-of-Stake block generation methods.

42 coin Review[edit]

42-coin was introduced in early January of 2014 on bitcointalk.org forum by user named hendo420. His idea was to create a "super rare" coin, with "only 42 coins to be mined". Denoting the meaning of life, according to Douglas Adams’ The Hitchhiker's Guide to The Galaxy, the number 42 in this case relates to the number used by 1950s American baseball player, Jackie Robinson. In 1997, Major League Baseball universally retired the use of his number 42 shirt number across all major league teams - a first in the history of the sport - driving the price of Robinson memorabilia through the roof.

At its peak value 42 was traded at the highest rate at 1900.00 BTC per one coin. At that time (13-Jan-2014), only 0.8 coins were in circulation, meaning this was the first crypto coin to exceed one million US dollars with less than 1 whole coin in circulation.

What is remarkable in the history of 42, is that until the spring of 2014 the coin supply was really capped at 42, but on March 17, 2014, the GitHub user sherlockcoin (aka soopy452000) made it unlimited. He was working under KGW implementation and no one noticed this "small change".

Meanwhile, the number of coins was growing, and the price was falling. On May 29, 2014 hendo420 left the project, he explained this by saying that:

“Hippie Tech's constant barrage and the constant price drop put me into a deep depression. My doctor prescribed me some medication that kind of helps but he recommended not to continue the activity that was causing me to be depressed/suicidal… I can’t emotionally continue…”

He handed the coin over to soopy452000, which surrendered after one month of work on the project.

On July 2015, Woodcoin developer, funkshelper when reviewing the code, saw that there was nothing, actually, stopping the coin supply from exceeding the apparently, number of 42. He submitted a pull request in order to fix this bug, but it was not merged in time, also there were no updated clients, so most people couldn’t support the chain with limited cap.

On October 26, 2015 hendo420 come back with promise to revive 42 and “get the total coins back under 42 without jeopardizing anyone's coins”. But after some time, he just closed all 42 threads on bitcointalk.org forum and gone without any explanations…

On June 07, 2016, after more than 7 month of waiting for a revival from hendo420 a new thread of 42-coin was started by another user, Lasergun. After 5 months of voting the community took a decision to return the original idea of limited supply by swapping old coins (84) for new (42) and add Proof-of-Stake as an additional method of transaction confirmation. In addition, the block time was increased from 42 seconds to 7 minutes, as it turned out that fast transactions are not really required in 42. A new blockchain based on Novacoin source code launched on November 12, 2016.

Where to buy 42 coin?[edit]

Coin42 is a very rare cryptocurrency, so 42 coin price is extra high. That's why not everybody can afford it. On May 18, 2018, the price of 42 coin is 30886,50 USD, but on January 29, 2018 it achieved 100030 USD per a coin.

42-coin price[edit]

The 42-coin prices are available online on CoinMarketCap widget:

Technical features[edit]


The transactions history is permanently recorded in the network through items called blocks. A block is a record of some or all of the most recent transactions that have not yet been recorded.

Block structure

Field Type Sizeof Description
Magic number Unsigned int 4 Always 0xE5E9E8E4
Block size Unsigned int 4 Number of bytes following up to end of block
Block header Struct 80 4Consists of 6 items
Transactions count Variable integer 1-9 -
Transactions set transaction Transactions size List of transactions
Header signature unsigned char <= 72 Signature for Proof-of-Stake is placed here.


A transaction is a signed section of data that is broadcast to the network and collected into blocks. It typically references previous transaction(s) and dedicates a certain number of 42 from it to one or more new public key(s). Currently there are a few transaction types possible.

User operation

These transactions are typically used to redeem 42 from unspent inputs. It generally references unspent input(s) and creates a new output(s) with specified value(s) and destination(s).


Coinbase have a single input, and this input has a 'coinbase' parameter instead of a scriptSig. The data in 'coinbase' can be anything; it isn't used. 42 puts the current compact-format target and the arbitrary-precision 'extraNonce' number there, which increments every time the Nonce field in the block header overflows. The extranonce contributes to enlarge the domain for the proof of work function.

These transactions are used to reward the Proof-of-Work miners. Proof-of-stake blocks have the coinbase transaction too, but with empty output.

These transactions are used to provide a suitable proof for Proof-of-Stake block header. This type is similar to user transactions, but with some differences.

  • First output must be empty;
  • First input of this transaction is required to satisfy a current Proof-of-Stake difficulty.
  • It's allowed to generate new coins through paying a negative fee.
  • A destination of the second output must be Pay-to-Pubkey (described later).

General format of a transaction

Field Type Sizeof Description
Version Unsigned int 4 Currently 1
Timestamp Unsigned int 4 Transaction timestamp
Inputs count Variable int 1-9 -
Inputs array TxIn inputs set size Inputs array or coinbase property
Outputs count Variable int 1-9 -
Outputs array TxOut outputs set size Array of output structures
Lock time unsigned int 4 block height or timestamp when transaction is final

Input format
An input is a reference to an output in a different transaction. Multiple inputs are often listed in a transaction. The values of the referenced outputs are added up, and the total is usable in the outputs of this transaction.

Field Type Sizeof Description
txid unsigned char 32 ID of previous transaction
n unsigned int 4 Number indexing an output of the to-be-consumed transaction
scriptSigLength variable int 1-9 scriptSig length
scriptSig unsigned char - first half of script, signatures for the scriptPubKey
nSequence unsigned int 4 Transaction variant number, irrelevant if nLockTime isn't specified. 0xffffffff by default, see this link for a detailed explanation.

Output format
An output contains instructions for sending 42. Value is the number of Satoshi (1 42 = 100,000,000 Satoshi, 1 Satoshi in 42 is also called “Dent”) that this output will be worth when claimed.

Field Type Sizeof Description
nValue unsigned long int 8 the number of Satoshis(42/108) to be transfered
scriptPubKeyLength variable int 1-9 scriptPubKey length
scriptPubKey unsigned char - second half of script, spending instructions

There are three destination types allowed for user and coinbase transactions:

  • Public key (Pay-to-Pubkey)

scriptPubKey: [pubKey] OP_CHECKSIG
scriptSig: [sig]

  • Public key hash (Pay-to-PubkeyHash)

scriptSig: [sig] [pubKey]

  • Script hash (Pay-to-ScriptHash)

Send to script hash:
scriptPubKey: OP_HASH160 [20-byte-hash of {[pubkey] OP_CHECKSIG} ] OP_EQUAL
scriptSig: <depending on inputs type>

Redeem example:
scriptPubKey: OP_HASH160 [20-byte-hash of {[pubkey] OP_CHECKSIG} ] OP_EQUAL
scriptSig: [signature] {[pubkey] OP_CHECKSIG}

  • Empty destination

scriptPubKey: (empty)
scriptSig: (empty)

  • Non-standard script

scriptPubKey: (empty)
scriptSig: OP_TRUE

42 coin wallet can be downloaded from GitHub.

42-coin Proof-of-Work[edit]

A proof-of-work is a solution for difficult (costly) mathematical task. This solution must be trivial to check whether data satisfies claimed requirements.

Currently proof-of-work remains the most practical way of providing initial minting of a crypto-currency. So we decided to keep it as part of our hybrid design.

42-coin uses the hashcash method to provide proofs of the work. The difficulty of this work is adjusted so as to limit the rate at which new blocks can be generated by the network to required target spacing rate (from 10 to 30 minutes). Due to the very low probability of successful proof generation, this makes it unpredictable which worker computer in the network will be able to generate the next solution.

How long will it take to generate a proof-of-work?
No one can say exactly. But there is an estimation of how long it might take.

Imagine that you have a hardware with 1 MH/s hashing speed. Let's estimate how much time the generation of proof-of-work will take from you in average, with a current 42-coin proof-of-work difficulty.

Difficulty 1.0 is represented by 0x00000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF value of target.

So, to get a successful proof of work we need to perform 0xFFFFFFFFFFFFFFFF / 0x00000000FFFFFFFF or ~ 4294967297 attempts.

At difficulty 360 we need ~ 360 * 4294967297 = 1546188226920 attempts. If you have 1 MH/s or 1000000 hashes per second, then you will be able to scan such amount of hashes within 1546188226920 / 1000000 = 1546188 seconds or 1546188 / 86400 = 17,89 days.

Probability of successful block generation during one day could be calculated from available hashrate using formula: P = nHashesPerSecond * 86400 / (4294967297 * difficulty)

How does it work?
Each block header represented by structure of 6 fields, a some of this fields could be varied pretty freely.

Field Type Sizeof Description
nVersion unsigned int 4 Shouldn't be modified manually
hashPrevBlock unsigned char 32 Shouldn't be modified manually
hashMerkleRoot unsigned char 32 It's a merkle tree hash. Could be modified through modification, addition or removal of transactions
nTime unsigned int 4 Can be updated manually to any value from [max tx timestamp, time() + 3600] interval
nBits unsigned int 4 Shouldn't be updated manually
nNonce unsigned int 4 Attempts counter for Proof-of-Work. You need to update this field for every new hashing attempt

What about rewards?
The block reward is zero, miners can only gather fees from transactions.

42-coin Proof-of-Stake[edit]

Proof of stake was introduced by Sunny King in Peercoin, alongside proof of work on the 19th August 2012. Proof-of-Stake is term referring to the use of currency itself (ownership) to achieve certain goals. In the 42 it is used to provide 42 coin mining and transaction processing on a par with Proof-of-Work.

42-coin uses the mixed Coin-Age/CoinDayWeight approach to provide proofs of the stake. The Proof-of-Stake difficulty is adjusted so as to limit the rate at which new blocks can be generated by the network to 7 minutes target spacing rate. Due to the very low probability of successful proof generation, this makes it unpredictable which computer in the network will be able to generate the next solution.

Coin Age
Coin age refers to the age of txn inputs. Coin age is equal to the number of coins sent times the average age on these coins. Age is measured in days. Age is reset to zero whenever a coin is sent AND whenever a coin provides a signature. Coin age could be used to calculate mandatory fees, block reward or proofhash target.

It's similar to coin age but age is calculated using 42-hours offset without upper limit. CoinDayWeight is a parameter of proofhash target in the proof-of-stake system.

nBlockTarget = CoinDayWeight * nNetworkTarget

Proof hash must satisfy the nBlockTarget, so greater CoinDayWeight means higher probability for generation of proof-of-stake block.

Coinstake kernel
Coinstake kernel it's a virtual structure which created during Proof-of-Stake block validation attempt. This structure exists in database and memory, but not on the network. The kernel parameters are described in the following table:

Field Type Sizeof Description
nStakeModifier unsigned long int 8 Deterministic modifier, scrambles computation to make it very difficult to precompute future Proof-of-Stake at the time of the coin's confirmation
nTimeBlockFrom unsigned int 4 Timestamp for block which provided previous transaction, prevent nodes from guessing a good timestamp to generate transaction for future advantage
nTxPrevOffset unsigned int 4 Offset of previous transaction inside the block, used to reduce the chance of nodes generating kernel coinstake at the same time
nTxPrevTime unsigned int 4 Timestamp of previous transaction, used to reduce the chance of nodes generating coinstake kernel at the same time
nPrevoutNum unsigned int 4 Output number of previous transaction, used to reduce the chance of nodes generating coinstake kernel at the same time
nTimeTx unsigned int 4 Current timestamp

How it's supposed to work?
It's performed through scanning all available inputs in order to find lucky one that satisfies following condition:

SHA256(SHA256(KERNEL)) < CoinDayWeight * NetworkTarget

Miner has to find a SHA256 hash that is under the target value. Target is derived from network target using CoinDayWeight parameter. The proof is presented by kernel hash and header signature. Each coinstake kernel represented by structure of 6 fields, a some of this fields could be varied pretty freely.

Field Type Sizeof Description
nStakeModifier unsigned long int 8 Shouldn't be modified manually
nTimeBlockFrom unsigned int 4 Timestamp for block which provided previous transaction
nTxPrevOffset unsigned int 4 Offset of previous transaction inside the block
nTxPrevTime unsigned int 4 Timestamp of previous transaction
nPrevoutNum unsigned int 4 Output number of previous transaction
nTimeTx unsigned int 4 Current timestamp

The hashing result of a valid Proof-of-Stake value must be lower than block target. Miner tries to find this suitable solution by scanning all available unspent inputs with suitable CoinDayWeight.

How long will it take to generate a Proof-of-Stake?
Just like with Proof-of-Work, no-one can say exactly. But there is an estimation of how long it might take. Calculations are quite similar with Proof-of-Work, but instead of hash we have coin * day-in-seconds here. So, at difficulty 1.0 we need ~ 4294967297 coin * day-in-seconds to find a block.

Probability of successful block generation during one day could be calculated from available CoinDayWeight using formula:

P = CoinDayWeight * 86400 / (4294967297 * difficulty)

Average block generation time could be calculated as:

T = 4294967297 * difficulty / (CoinDayWeight * 86400)

When it is possible to start generating Proof-of-Stake blocks?
If you have balance, then 42d would automatically try to generate proof hashes for you.

What about rewards?
The block reward is zero and, and fees are destroyed in PoS blocks - this makes 42 a deflationary coin

42 coin Mining and Blockchain[edit]

Mining is a term referring to the generation of new blocks for 42-coin blockchain. It's required to provide confirmations for transactions and to protect the history of operations.

Block header
The block header is a metadata structure which is used to link blocks in the blockchain. Block header has a size of 80 bytes and consists of 6 fields:

Field Type Sizeof Description Updated when
nVersion unsigned int 4 Block header version You upgrade the software and it specifies a new version
hashPrevBlock unsigned char 32 Previous block header hash, used to link block headers into list New block is accepted
hashMerkleRoot unsigned char 32 Merkle tree hash, used to link block header and block contents Transactions pool is updated
nTime unsigned int 4 Unix timestamp Every few seconds for Proof-of-Work, every successful attempt for Proof-of-Stake
nBits unsigned int 4 Compact representation of claimed proof difficulty The difficulty is adjusted
nNonce unsigned int 4 Attempts counter for Proof-of-Work New Proof-of-Work hash tried, or never with Proof-of-Stake

Each block header is required to satisfy the claimed proof.

How is it supposed to work?
All miners have a copy of every unconfirmed valid transaction in own transactions pool. Normally mining process is performed in the four stages:

  • Get a set of transactions from transactions pool;
  • Calculate a merkle tree hash for this set of transactions;
  • Create block header template and link it with this set of transactions using its merkle tree hash;
  • Try to find suitable proof hash for block header created before.

Getting a proof is quite a difficult operation, the difficulty depends on the current number of participants. Each block header is linked to previous block header, so we have linked list of block headers, and a list consistency is guaranteed by difficulty. This linked list is also known as blockchain.

What can be used as a proof?
The only required property of proof is that it's extremely difficult to obtain, but very easy to check. There are a lot of proof concepts in existence, such as proof-of-work, proof-of-stake or proof-of-burn. 42-coin supports usage of stake or work to provide suitable proof for block header.

Configuration file example
Please note that the following example isn't purposed for production use. It was placed here to help describe the purpose of some of the settings.

# 42.conf configuration file. Lines beginning with # are comments.
# Network-related settings:
# Run on the test network instead of the real 42-coin network.
# Connect via a socks4 proxy - default none
# Accepting incoming connections
# Use as many addnode= settings as you like to connect to specific peers
# ... or use as many connect= settings as you like to connect ONLY
# to specific peers:
#Maximum number of inbound+outbound connections.
# JSON-RPC options (for controlling a running 42d process)
# You must set rpcuser and rpcpassword to secure the JSON-RPC api
# How many seconds 42-coin will wait for a complete RPC HTTP request after the HTTP connection is established. 
# By default, only RPC connections from localhost are allowed.  Specify as many rpcallowip= settings as you like to allow connections from other hosts (and you may use * as a wildcard character):
# Listen for RPC connections on this TCP port:
# You can use 42d to send commands to 42d running on another host using this option:
# Use Secure Sockets Layer (also known as TLS or HTTPS) to communicate with 42d
# OpenSSL settings used when rpcssl=1
# Miscellaneous options
# Pre-generate this many public/private key pairs, so wallet backups will be valid for both prior transactions and several dozen future transactions.
# Data directory path, your keys store, copy of blockchain and unspent outputs index are stored here.
# Wallet file name
# Checkpoints policy (possible values are strict and advisory)
# Require confirmations for change (disabled by default)
# Enforce transaction scripts to use canonical PUSH operators enforcecanonical=1

42 coin exchanges and markets[edit]

Cryptopia.co.nz: 42/BTC, 42/DOGE, 42/LTC - Deposit Confirmations: 200 blocks, Trade Fee: 0.2%, Withdrawal Fee: 0.00000002, Minimum trade: 0.00005 BTC

LiveCoin.net: 42/BTC, 42/USD, 42/ETH - Deposit Confirmations: 8 blocks, Trade Fee: 0.2-%, Withdrawal Fee: 0.000001, Minimum trade: 0.0001 BTC

TradeSatoshi.com: 42/BTC, 42/BCH, 42/LTC, 42/DOGE - Deposit Confirmations: 12 blocks, Trade Fee: 0.2%, Withdrawal Fee: 0.00000002, Minimum trade: 0.000005 BTC

CoinsMarkets.com: 42/BTC - Deposit Confirmations: ? blocks, Trade Fee: 0.25%, Withdrawal Fee: 0.00000003, Minimum trade: 0.00001 42

NovaExchange.com: 42/BTC, 42/DOGE, 42/ETH, 42/LTC, 42/MOON, 42/KIC - Deposit Confirmations: 40 blocks, Trade Fee: 0.2%, Withdrawal Fee: 0.00000001, Minimum trade: 0.0000002 BTC