Pascal Coin: P2P Cryptocurrency without need of historical operations.

Copyright (c) 2016 Albert Molina

THIS IS EXPERIMENTAL SOFTWARE. Use it for educational purposes only.

This software is a Node of the Pascal Coin P2P Cryptocurrency.
It can be used to Mine and Explore blocks and operations.

Distributed under the MIT software license, see the accompanying file
LICENSE or visit http://www.opensource.org/licenses/mit-license.php.

This product includes software developed by the OpenSSL Project and Denis
Grinyuk (https://github.com/Arvur/OpenSSL-Delphi), and some
cryptographic functions inspirated in code written by Ladar Levison and
Marco Ferrante.
Original source code is written in Pascal Language and is available at
https://github.com/PascalCoin/PascalCoin

HOW TO COMPILE:

See instructions at GitHub Wiki: https://github.com/PascalCoin/PascalCoin/wiki

Enjoy Pascal Coin!

Donations

If you like it, consider a donation using BitCoin: 16K3HCZRhFUtM8GdWRcfKeaa6KsuyxZaYk

Also, consider a donation at PascalCoin development account: "0-10"

History:

Build 2.1.3.0 - 2017-11-15

• Fixed BUG when buying account assigning an invalid public key
• Added maxim value to node servers buffer, deleting old node servers not used, this improves speed
• Re-add orphaned operations back into the pending pool
• RPC locking to prevent N_Operation race-condition on concurrent invocations
• Minor bugs

Build 2.1.2.0 - 2017-07-27

• No more blockchain in installer = TRUE DELETABLE BLOCKCHAIN (Safebox will be automatically downloaded by client from network)
• Fixed storage bug when downloading a new safebox
• Safebox will be downloaded in small chunks (aprox 2mb per chunk)
• Read safebox file improvements (quick start)

Build 2.1.1.0 - 2017-07-16

• Fixed installer bug: In last Windows installer a malformed safebox file was included. This build is only to provide a good safebox file with the installer
• No important changes in exe/binary file

Build 2.1.0.0 - 2017-07-14

• Fixed bug of slow mass transactions from a single account due to incorrect sending order
• Fixed memory leak on GetSafeBox request call
• Added new GUI improvements on Operations form

Build 2.0.0.0 - 2017-06-23

• MANDATORY UPGRADE - HARD FORK ACTIVATION WILL OCCUR ON BLOCK 115000
• Introducing Protocol v2.
  • https://github.com/PascalCoin/PascalCoin/blob/master/PascalCoinWhitePaperV2.pdf
  • Core Changes:
    • New safebox hash calculation algorithm to allow safebox checkpointing
    • Improved difficulty target calculation to obtain a more stable average blocktime of 5 minutes, given abrupt hashpower fluctuations
    • Bug-fix for China region users
    • Anti-spam measures
      • New Consensus Rule: A block can only contain 1 zero fee operation per sender account. If a sender account issues 2 or more zero-fee operations, that block is invalid.
    • SafeBox now stored in chunks to facilitate checkpoint distribution
    • Reintroduce orphan blocks operations on main blockchain
  • Added Checkpointing:
    • Checkpoint created on every 100'th block
    • Added network operations to transfer Checkpoint chunks (compressed)
  • Addded In-Protocol PASA Exchanging:
    • New Operation: List Account, used to list an account for public or private sale
    • New Operation: Delist Account, used to delist an account from sale
    • New Operation: Buy Account, used to purchase an account lised for sale
    • Updated Operation: Transaction, can be used in place of Buy Account operation in private account sales
  • RPC API Changes:
    • All changes are backwards-compatible for current 3rd-party infrastructure providers (exchanges, wallets).
    • However, use of param "ophash" has been changed in V2, see "Operation Object changes" section to know how to use "old_ophash" param value
    • JSON changes:
      • Account Object changes:
        • Added param "state" (values can be "normal" or "listed". When listed then account is for sale)
        • If "state" is "listed" then will fill next values:
          • "locked_until_block", "price", "seller_account"
          • "private_sale" : Boolean value
          • "new_enc_pubkey" : (Only on "private_sale" = true) - HEXASTRING with private sale encoded public key
        • Added param "name": String
          • Name available chars: abcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()-+{}[]_:"|<>,.?/~
          • Name first char: (cannot start with number): abcdefghijklmnopqrstuvwxyz!@#$%^&*()-+{}[]_:"|<>,.?/~
          • Name lenght: Empty or 3..64 chars length
        • Added param "type": Integer (Valid values from 0..65535)
      • Operation Object changes:
        • Changed param "ophash": Current returned value of "ophash" is not the same than previous builds (changed calculation method)
        • New param "old_ophash": Will return previous "ophash" value only for old blocks (prior to v2 protocol activation)
        • New param "subtype" : Based on "optype" param, this param allows to discrimine point of view of operation (sender/receiver/buyer/seller ...)
        • New param "signer_account" : Will return the account that signed (and payed fee) for this operation
        • Param "enc_pubkey": Will return both change key and the private sale public key value
        • About method "findoperation" and "ophash"
          • Due to changed "ophash" param value calculation, method "findoperation" will find old "ophash" values too
          • This is to avoid 100% compatibility, but remember that returned "Operation object" will contain "ophash" value calculated in new format only (you can read "old_ophash" value in older blocks)
      • New methods:
        • "listaccountforsale" : Lists an account for sale (public or private)
          • Params:
            • "account_target" : Account to be listed
            • "account_signer" : Account that signs and pays the fee (must have same public key that listed account, or be the same)
            • "price": price account can be purchased for
            • "seller_account" : Account that will receive "price" amount on sell
            • "new_b58_pubkey"/"new_enc_pubkey": If used, then will be a private sale
            • "locked_until_block" : Block number until this account will be locked (a locked account cannot execute operations while locked)
            • "fee","payload","payload_method","pwd"
        • "signlistaccountforsale" : Signs a List an account for sale (public or private) for cold wallets
          • Params: Same "listaccountforsale" params, and also:
            • "rawoperations" : HEXASTRING with previous signed operations (optional)
            • "signer_b58_pubkey"/"signer_enc_pubkey" : The current public key of "account_signer"
            • "last_n_operation" : The current n_operation of signer account
        • "delistaccountforsale" : Delist an account for sale
          • Params:
            • "account_target" : Account to be delisted
            • "account_signer" : Account that signs and pays the fee (must have same public key that delisted account, or be the same)
            • "fee","payload","payload_method","pwd"
        • "signdelistaccountforsale" : Signs a List an account for sale (public or private) for cold wallets
          • Params: Same "delistaccountforsale" params, and also:
            • "rawoperations" : HEXASTRING with previous signed operations (optional)
            • "signer_b58_pubkey"/"signer_enc_pubkey" : The current public key of "account_signer"
            • "last_n_operation" : The current n_operation of signer account
        • "buyaccount" : Buy an account previously listed for sale (public or private)
          • Params:
            • "buyer_account","account_to_purchase",
            • "price","seller_account",
            • "new_b58_pubkey"/"new_enc_pubkey","amount",
            • "fee","payload","payload_method","pwd"
        • "signbuyaccount" : Signs a buy operation for cold wallets
          • Params: Same "buyaccount" params, and also:
            • "rawoperations" : HEXASTRING with previous signed operations (optional)
            • "signer_b58_pubkey"/"signer_enc_pubkey" : The current public key of "buyer_account"
            • "last_n_operation" : The current n_operation of buyer account
        • "changeaccountinfo" : Changes an account Public key, or name, or type value (at least 1 on 3)
          • Params:
          • "account_target" : Account to be delisted
          • "account_signer" : Account that signs and pays the fee (must have same public key that target account, or be the same)
          • "new_b58_pubkey"/"new_enc_pubkey": If used, then will change the target account public key
          • "new_name": If used, then will change the target account name
          • "new_type": If used, then will change the target account type
          • "fee","payload","payload_method","pwd"
        • "signchangeaccountinfo" : Signs a change account info for cold cold wallets
          • Params: Same "changeaccountinfo" params, and also:
            • "rawoperations" : HEXASTRING with previous signed operations (optional)
            • "signer_b58_pubkey"/"signer_enc_pubkey" : The current public key of "account_signer"
            • "last_n_operation" : The current n_operation of signer account
        • "findaccounts" : Find accounts by name/type and returns them as an array of Account objects
          • Returned array will be sorted by account number
          • Params:
            • "name" : (String) If has value, will return the account that match name
            • "type" : (Integer) If has value, will return accounts with same type
            • "start" : (Integer) Start account (by default, 0)
            • "max" : (Integer) Max of accounts returned in array (by default, 100)
      • Updated methods:
        • "changekey" : Added param "account_signer" that allow to pay fee using another account with same public key than target "account" param. This allows to change keys on empty accounts (balance = 0) and pay fee
        • "signchangekey" : Added param "account_signer", same use that in "changekey" method
  • GUI changes: (not available on daemon)
    • New columns "name" and "type" on accounts
    • Information about Accounts/Operation using F1
    • Operations form now accepts: (Will be active after V2 protocol activation)
      • List account for sale (public or private)
      • Delist account
      • Buy account
      • Change account name/type
    • Operations form allows to search for accounts using F2 over an account edit box
    • Changes in text showing operations information
• Other changes:
  • Bug for china users fixed
  • Bugs fixed

Build 1.5.6.0 - 2017-05-03

• Allow multiselect accounts (GUI wallet)
• Priority for operations with fee:
  • Allow miner server (pools) to select what to mine using pascalcoin_daemon.ini file (daemon only)
    • RPC_SERVERMINER_MAX_OPERATIONS_PER_BLOCK: Max of operations that can be included in a block (Default 5000, min value 1000)
    • RPC_SERVERMINER_MAX_ZERO_FEE_OPERATIONS: Max of operations with 0 fee that can be included in a block (Default 2000, min value 400)
  • Operations with fee have always preference over 0 fee operations (will be mined first)
  • If operations with fee fills all the buffer, then no zero fee operation will be included
• Fixed bug on receiving big blocks and slow net connection to prevent never synchronize
• Fixed bug on miner server that produces "invalid operations hash" error on valid solutions with 0 operations
• Fixed bug on file storage
• Fixed minor bugs

Build 1.5.5.0 - 2017-04-11

• Corrected fee result on RPC calls as a negative number on "Change key" operations
• Corrected PASCURRENCY value to be limited as a 4 decimal digits on RPC calls
• JSON-RPC method "getaccountoperations" changed: if param "start" is -1, will include pending operations, otherwise not
• Fixed bug: On "getaccountoperations" if an account had a lot of operations (receive tx included) then sometimes app crashed when executing depth search.
  • Note: High depth search is slow because it search always starting from current state, going backwards, in order to return past balance. This can be a slow method on some account with high transactions volume.

Build 1.5.4.0 - 2017-03-14

• Added Network Timestamp Adjustment (NAT) to calc valid timestamps
  • Minimum 4 active connections to calc median used for NAT, otherwise use local timestamp
  • Based on IP's (to prevent a malicious IP timejacking, each IP is only used once)
  • Removed IP's and recalculated after disconnecting (to prevent malicious node connecting/disconnecting for timejacking)
• New blocks will not be accepted if using future timestamp greater than NAT timestamp + 15 seconds (also, mantaining current protocol rule >= lastBlock.timestamp)
• Network protocol fixed to 5-5 (Nodes with version prior to 1.5 will not be allowed)
• Added protection for non included operations on a block, to prevent continuous sending. Only will resend operations once.
• Bug #27 fixed: Invalid timestamp on FPC (PascalCoin#27)
• JSON-RPC
  • Method "getconnections" added "timediff" to know timestamp diff of node
  • Method "payloaddecrypt" added "unenc_hexpayload" result value with HEXASTRING of unencrypted payload
• Fixed some "Random Memory access violation errors" bugs found caused by multithreading and disconnected nodes

Build 1.5.3.0 - 2017-03-06

• Fixed issue #23: RPC findoperation fails to find operation by opHash
• Miners best practices: Sending new job with new timestamp every 30 seconds
• Buffering last 10 sent jobs to miners
• Small delay prior to destroy a connection to prevent exception handling
• Minor logs changes

Build 1.5.2.0 - 2017-03-03

• Added a jobs buffer for miners. This will allow to submit old job solutions (limited buffer). (Fix the "tx" issue)
• Miner jobs will not be sent every time a transaction is received, thet will be buffered and sent every few seconds (Fix the "tx" issue)
• Better network performance, allowing more operations and nodes thanks to buffering before relaying
• Daemon: Allow select on ini file how many connections can handle
• Fixed a locking when deleting connections

Build 1.5.1.0 - 2017-02-20

• Memory leak fixed on RPC-JSON commands
• Memory leak fixed on node connections
• Improved network speed processing new blocks/operations
• Some minor bugs

Build 1.5.0.0 - 2017-02-15

• Net protocol upgrade to 4-5
• Introducing "more work" with high priority than "more high". Work is calculated based on target. Higher target (more work) is more important than higher length
• Solved locking/crash bug on high connections (caused by bad thread locking)
• Improved network connection
• Added JSON-RPC port 4003 protection Whitelist (only allowed IP's can use JSON-RPC)

Build 1.4.3.0 - 2017-02-02

• Adding "maturation" param to "JSON Operation object", return null when operation is not included on a blockchain yet, 0 means that is included in highest block and so on...
• Fixing miner timestamp value to prevent invalid time

Build 1.4.2.0 - 2017-01-23

• Max JSON-RPC miner connections is now 1000 (before, 10)
• JSON-RPC miner enabled at pascalcoin_daemon (linux daemon)
• Screen messages for daemon
• pascalcoin_daemon.ini file for daemon

Build 1.4.1.0 - 2017-01-18

• Improved JSON communications with Miner client (Port 4009 by default)
• Deleted adding numeration to JSON miner clients (only sends miner name)
• Minor changes

Build 1.4.0.0 - 2016-12-30

• JSON-RPC changes:
  • Added method "signsendto" to allow a off-line wallet sign transaction operations without being syncrhonized
  • Added method "signchangekey" to allow a off-line wallet sign change key operations without being syncrhonized
  • Added method "executeoperations" to allow a on-line wallet execute operations signed off-line
  • Added method "operationsinfo" that will decode operations signed off-line
  • Added param "max" at JSON-RPC method "getblocks"
  • Changed param name "deep" for "depht" in "getaccountoperations". Deep will be available for compatibility.
  • Changed result for "changekeys". Now returns a "JSON operation object" array with each change key operation result
  • Changes on "JSON Operation object": May return a "valid" param and "errors" param
• Corrected a memory leak when processing JSON-RPC calls
• Better performance in connection protocol
• Updated protocol available to 1
• Updated net protocol to 3-4
• Important bug corrected

Build 1.3.0.0 - 2016-11-24

• JSON-RPC modifications:
  • New param "b58_pubkey", can be used instead of "enc_pubkey": b58_pubkey is a Base58 encoded public key with checksum, is the value that Wallet exports/imports public key
  • New JSON object type Public Key: "name","can_use","enc_pubkey","b58_pubkey","ec_nid","x" and "y" for each public key
  • Added params "start" and "max" to "getaccountoperations". By default deep=100, max=100 and start=0, so will return last 100 operations made to an account
  • Added params "start" and "max" to "getblockoperations". By default max=100 and start=0, so will return last 100 operations made to a block
  • Added params "start" and "max" to "getwalletaccounts". By default max=100 and start=0, so will return first 100 accounts of the wallet
  • Added params "start" and "max" to "getwalletpubkeys". By default max=100 and start=0, so will return first 100 public keys of the wallet
    • Will return a Public key JSON object
  • Method "decodepubkey" allows params "enc_pubkey" or "b58_pubkey" (if used together, returns error if not match)
    • Will return a Public key JSON object
  • Method "changekey" allows params "new_enc_pubkey" or "new_b58_pubkey" (if used together, returns error if not match)
  • Method "getwalletaccounts" allows params "enc_pubkey" or "b58_pubkey" (if used together, returns error if not match)
  • Method "getwalletaccountscount" allows params "enc_pubkey" or "b58_pubkey" (if used together, returns error if not match)
  • Method "getwalletcoins" allows params "enc_pubkey" or "b58_pubkey" (if used together, returns error if not match)
  • Method "payloadencrypt" allows params "enc_pubkey" or "b58_pubkey" when payload_method="pubkey" (if used together, returns error if not match)
  • Method "addnewkey" changed. Does not return an HEXASTRING with enc_pubkey, now returns a public key JSON object
  • New methods:
    • Method "changekeys". Similar to "changekey" but for multiple accounts at param "accounts" as a coma separated string (ex: "accounts"="1248,1753,85056"). Returns a JSON object with result information
    • Method "lock" to lock wallet. Returns true if locked, returns false if wallet has no password (an empty string, must put a new password prior to lock)
    • New method "getwalletpubkey". Search for "enc_pubkey" or "b58_pubkey" and returns a Public key JSON object
• Corrected a issue saving last 5 .bank files
• Improved protections for .bank corruption files
• Added "open data folder" button on options form
• Other minor changes

Build 1.2.0.0 - 2016-11-16

• Account checksum values modified to be more easy and more distributed: Checksum = ((N * 101) MOD 89)+10
• Allow find operations by "ophash"
• Show Operation "ophash" in operation payload decoder
• Added param "enc_pubkey" to "getwalletaccounts" JSON-RPC method to return only accounts from this public key
• Added params "pow" and "sbh" to "nodestatus" JSON-RPC method
• Added method "getwalletaccountscount" returning accounts count of the entire wallet or for a single "enc_pubkey"
• Added method "getwalletcoins" returning coins of the entire wallet or for a signle "enc_pubkey"
• Modified seed nodes distribution to send only checked IP nodes
• Corrected invalid operation block index when showing account operations

Build 1.1.0.0 - 2016-11-03

• JSON-RPC Server included
• Minor changes

Build 1.0.9.0 - 2016-10-21

• Corrected a BUG (BUG-101) that causes blocking connections when received more than 100 connections, causing "alone in the world" after a cert period time.
• It's necessary to update because new version will refuse old versions to make network stable.

Build 1.0.8.0 - 2016-10-20

• Cross compatible
• Can compile with Delphi or Lazarus (Free Pascal)
• New storage system. No more access database
• Network hashrate calculation

Build 1.0.7.0 - 2016-10-10

• Introducing basic JSON-RPC to allow GPU miners development (Third party).
• See file "HOWTO_DEVELOP_GPU_MINER_FOR_PASCALCOIN.txt"
• No more CPU mining due exists GPU mining

Build 1.0.6.0 - 2016-10-04

• Memory leaks corrections
• Introducing net protocol 2-3
• Source code modified, next build will be compiled with Lazarus and FPC

Build 1.0.5.0 - 2016-09-21

• Massive operations, selecting multiple accounts
• Filter accounts by balance
• Correct operations explorer order of operations for each block (descending order)
• Minor changes

Build 1.0.4.0 - 2016-09-16

• IMPORTANT: Introducing net protocol changes: Must update!
• More and more and more stable
• Prevents "Alone in the world" if everybody is updated ;-)
• Invalid local time detector with corrections
• IP nodes configurator

Build 1.0.3.0 - 2016-09-08

• Important changes to database
• Peer cache
• Issues with Connections
• More stable
• Miner key selector
• Invalid local time detector

Build 1.0.2.0 - 2016-08-31

• Improved hashing speed
• Allow mining without opening external ports
• Choose how many CPU's want to mine
• Show real-time pending operations waiting to be included in the block
• More stable
• Some miner modifications

Build 1.0.1.0 - 2016-08-12

• Included an option to Import/Export Wallet keys file
• Some miner modifications

Build 1.0.0.0 - 2016-08-11

• First stable version.
• Created with Genesis block hardcoded
• Published at same time than Genesis block. NO PREMINE