Colored Coins – Bitcoin Wiki

The term “ colored Coins ” loosely describes a classify of methods for representing and managing real world assets on lead of the Bitcoin Blockchain. While originally designed to be a currentness, Bitcoin ‘s script linguistic process allows to store minor amounts of metadata on the blockchain, which can be used to represent asset manipulation instructions. For exercise, we can encode in a Bitcoin transaction that 100 units of a new asset were issued and are now credited to a given bitcoin savoir-faire. A colored coins wallet can create a Bitcoin transaction that encodes sending 50 units of an asset from one address to a new savoir-faire, and indeed on. real number world Value is attached to those units ( or “ digital tokens ” ) by the asset issuer ‘s promise to redeem them for some goods or services. For case, a 100 seat movie field can issue 100 units of a “ watch movie ten at time Y ” asset and promise to redeem each unit for a right to enter a certain screen of a movie. The advantage of using Bitcoin ‘s blockchain as the spine leverages Bitcoin ‘s strengths, such as immutability, non-counterfeitability, rest of transfer, robustness and transparency thus allowing asset handling with unprecedented security and rest.

In principle one can represent asset handling data on other blockchains. The term “ tinge Coins ” is normally associated with implementations that

  • Use the Bitcoin blockchain
  • Do not issue an auxiliary coin

bill that the term Colored Coins stick from older implementations such as the EPOBC protocol where an asset was actually associated with satoshis ( therefore “ coloring ” them ). early implementations use other ways to encode assets on the blockchain, largely using the OP_RETURN script code, so it is nobelium farseeing the only case that individual satoshis are “ colored ” .

Use Cases

There are many matter to applications to colored mint .

Issuing shares

A company can issue shares using color coins, taking advantage of the Bitcoin infrastructure for activities such as

  • Trading
  • Voting
  • Paying dividends

Smart property

Suppose there is a car rental company. The ship’s company can release one colored mint to represent each car, and then configure the car to turn on only if it receives a message signed with the private key that presently owns the colored mint. It can then release a smartphone app that anyone can use to broadcast a message signed with their private key, and put up the colored coins on a trade platform. Anyone will be able to then purchase a colored person coin, use the car for whatever period of time using the smartphone app as a “ cable car key ”, and sell the mint again at their leisure .


A ship’s company may wish to issue coupons, such as Air Miles rewards points

Community Money

A community. e.g. a town, can issue it ‘s own Currency .

Digital collectibles

Decentralized management of digital assets. Just like artwork collectors buy and sell master copies of celebrated paintings for millions of dollars nowadays, colored coins allow us to do the same with strictly digital objects, such as songs, movies, e-books and software, a well, by storing the current ownership of the work as a tinge coin on the blockchain .

Access and Subscription

Using color coins to trade and manage access and subscription services. For exemplar, a museum, a metro or an on-line service like Netflix may issue passes as color coins and release a smartphone app that can be used to make a signature proving possession of a evanesce in person, allowing these passes to be simultaneously movable, amply digital and securely uncopyable .

Bitcoin 2.0

Using the exponent of Bitcoin Blockchain engineering for fresh use-cases other than currency

  • The next generation of bitcoin developments
  • Utilizing the power of Bitcoin Blockchain for new use-cases other than currency and extending its flexibility
  • Wider range of digital transactions
  • A complete multi asset economy

capable Assets Block Explorer

Coinprism offers a color coin Bitcoin blockchain explorer .

Colu ‘s Block Explorer offers a public search engine for digital assets, all outdoors beginning based on the Colu Coloredcoins implementation

The EPOBC protocol

EPOBC is the first Coloredcoins execution which was created By ChromaWay. EPOBC does n’t use op_return to store metadata on the blockchain

Types of transactions

EPOBC introduces two types of transactions : • genesis transactions create new color coins ( of a new color ) ; they are used for issue • remove transactions transfers existing colored coins If colored coins are used as inputs in a transaction which is n’t a transfer transaction, their prize is lost, it is not transferred to outputs of this or early transaction. besides the prize of colored person coins might be lost in a deformed transaction .

EPOBC-encoded colored mint transactions are marked in a special way to distinguish them from normal Bitcoin transactions. This is done by putting a certain tag measure into a nSequence field of transaction ‘s inaugural input. nSequence is constantly show, but is otherwise unused, which means that this means of tag has zero overhead ( unlike OP_RETURN-based which increases the size of the transaction ). nSequence is a 32-bit integer, and 6 of its least-significant bits encode the tag. Transfer transactions and genesis transactions have different tags : • snatch sequence 110011 is a chase of a transfer transaction. Its hexadecimal rate is 0x33. • bite sequence 100101 is a tag of a genesis transaction. Its hexadecimal rate is 0x25. Code which distinguishes transfer and genesis transaction :

  1. get nSequence of the first input

tag_nSequence = transaction.inputs [ 0 ] .nSequence

  1. extract its lowest 6 bits

tag = tag_nSequence & 0x3F if tag == 0x25 :

   transaction_type = 'genesis'

elif tag == 0x33 :

   transaction_type = 'transfer'

else :

   transaction_type = 'none'

foster treatment depends on transaction type. however, both transmit and genesis transactions have padding. EPOBC is the first Coloredcoins protocol to have subscribe for dilute SPV clients .

Current projects/companies which are leveraging EPOBC

open Assets

candid Assets is a Colored Coin implementation based on the OP_RETURN operator. Metadata is linked from the Blockchain and stored on the world wide web .

model of an Open Assets OP_RETURN marker output

This exemplar illustrates how a marker end product is decoded. Assuming the marker output is output 1 :

   Data in the marker output      Description
   -----------------------------  -------------------------------------------------------------------
   0x6a                           The OP_RETURN opcode.
   0x10                           The marker output is 16 bytes long.
   0x4f 0x41                      The Open Assets Protocol tag.
   0x01 0x00                      Version 1 of the protocol.
   0x03                           There are 3 items in the asset quantity list.
   0xac 0x02 0x00 0xe5 0x8e 0x26  The asset quantity list:
                                  - '0xac 0x02' means output 0 has an asset quantity of 300.
                                  - Output 1 is skipped and has an asset quantity of 0
                                    because it is the marker output.
                                  - '0x00' means output 2 has an asset quantity of 0.
                                  - '0xe5 0x8e 0x26' means output 3 has an asset quantity of 624,485.
                                  - Outputs after output 3 (if any) have an asset quantity of 0.
   0x04                           The metadata is 4 bytes long.
   0x12 0x34 0x56 0x78            Some arbitrary metadata.

current projects leveraging Open Assets


CoinSpark is a Colored Coin implementation that uses a lightweight ( SPV ) background wallet for Windows, Mac or Linux. In CoinSpark, contracts are hosted on the issuer ‘s web site and notarized on the blockchain. Like Open Assets, it uses OP_RETURNs to store metadata, with a highly effective encoding outline that allows multiple transfers of different assets to be encoded in a unmarried transaction. CoinSpark software libraries are available for C/C++, Java, Javascript, PHP and Python, and there ‘s a detail developers guide with examples .

Colu Colored Coins Implementation

A new Colored Coins implementation was developed by Colu and amply open sourced on June 2015. The raw implementation is based on attaching data to transactions using the OP_RETURN field. Colu ‘s coloring scheme uses high data compaction, can associate unlimited amounts of metadata with bitcoin transactions through the use of publicly available torrent files and supports smart compress functionalities.

chief Features

Smarts Contracts capabilities

A Rule Engine for issuing digital assets with respective capabilities : termination dates, restricted access, extra fees ( supporting consort market ), limitations on promote issue, etc .

Using Torrents for Metadata storage

Metadata is stored in publicly available downpour files, alone a mention is stored directly on the blockchain. This allows for

  • Maximal Decentralization
  • Unlimited Size – Since metadata is not stored directly on the blockchain it’s size is unlimited and can contain information like: track record, history, description, validity or any information the issuer finds relevant.

flexible metadata cover

Adding metadata on every transaction, supporting the addition of relevant metadata that was not so far available during issue ( e.g. mentioning a specific seat count on a movie theater nominal ) .

coherent issue policy

Enforcing a coherent issue policy by supporting two types of assets, locked and unlock .

  • Locked Assets – A fixed amount is defined during issuance. No one can issue more units of the asset, not even the issuer.
  • Unlocked Assets – The issuer can keep issuing more units.

defend for thin ( SPV ) wallets

The raw colu execution supports SPV clients – nodes that can * * * verify colored transactions * * * without running a full moon Bitcoin node.

efficiency and Low Cost

  • Data compression – high level of data compression using a precision encoding scheme for encoding asset issuance and transfer amounts.
  • Sending Multiple Assets in Single Transaction
  • Minimal Blockchain Bloat

subscribe for Zero Confirmations

The new computer architecture supports asset issue and transfer in zero confirmations ( even within the lapp transaction ) – the Asset ID references only the first UTXO in the transaction and makes no reference to a block .


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