Coin Dance

Revised DAA (w/ PID control)

 Bitcoin ABC | Bitcoin XT

Revise Difficulty Adjustment Algorithm to further improve block times using a new PID control algorithm

Bobtail

A Proof-of-Work Target that Minimizes Blockchain Mining Variance

One Way Aggregate Signatures

 Electron Cash

A non-interactive fungibility solution for transactional privacy.

Switch standard denomination to 'bits'

Switch the standard denomination of Bitcoin Cash to 'bits' (1 millionth of a Bitcoin) and switch the ticker from 'BCH' to 'BIT'.

Representative Tokens (GROUP)

 Bitcoin Unlimited

Enable representative tokens via GROUP

Chain ID

 Bitcoin ABC | nChain | Electron Cash

A simple, yet powerful way to provide more human friendly front ends. The main use is to identify the user by name -or nickname- and mobile phone so wallets have data from users and users can pay to human understandable names instead of cryptographic hashes.

Avalanche

 Team Rocket

Allow miners to come to consensus on double spend transactions before they have been mined into a block (pre-consensus).

Recursive Smelting

A Token Layer Protocol on Bitcoin Cash

Improved 0-conf via security deposits

 Bitcoin Unlimited

the consumer will make a special ZCF transaction that pays the merchant and simultaneously posts a security deposit. If the transaction is honest, the consumer can later reclaim his deposit. If he tries to double spend, he necessarily reveals a second signature over the same public key which is then used by miners to claim his deposit for themselves. Pretty clever!

BLS Signatures

BLS signatures allow combining all signatures in a block to a single signature. We can use key aggregation and a m-of-n multisig scheme without additional communication rounds without needing to rely on random number generators.

OpenCAP alias protocol

OpenCAP is a protocol that defines the standard by which cryptocurrency wallets can communicate with servers to relate aliases to cryptocurrency addresses.

The protocol allows for the decentralization of the alias -> address relationship.

Maxblocksize Based on Median Block Size

The basic idea is that we look at recent block history. We calculate recent usage and use it to set a new limit that is much higher. We adjust every time a new block is found. With this the blocks are unlikely to ever go full, even at load peaks.

Time Delay Penalty Based on Multiple Blocks

Preven deep re-org attacks by penalizing alternate chaintips by a factor that is calculated by averaging the delays (in seconds) of each opposing block.

UTXO commitments

 Bitcoin ABC | bitCrust

The construction of a 32-byte hash that is uniquely defined for a UTXO set, that is, the set of all unspent transaction outputs that exist at a certain block in the blockchain

BUIP087 nomenclature for 1/1,000,000 BCH

 Bitcoin Unlimited

Add "cash" in addition to "bit" as a term for 100 (one hundred) satoshi or 1/1,000,000 (one one-millionth) of a bitcoin cash BCH (i.e. 0.000001 BCH). Further, we propose the unofficial ISO code "XCH" to represent a cash unit (millionth of a BCH unit). -- UPDATE: For French translations only.

Modified fee structure

 Bitcoin ABC

Modified fee structure to allow for an order of magnitude decrease in fees for typical transactions (not strictly a consensus change, but an important change being included with the release).

Cash ID

CashID is an open protocol that allows secure authentication based on the public key cryptography infrastructure that is currently present in the Bitcoin Cash ecosystem. Each user can prove to a service provider that they control a specific Bitcoin Cash address by signing a challenge request, as well as provide optional metadata.

Cash Accounts

 Electron Cash

Cash Accounts is a naming system that can be used alongside regular bitcoin addresses and payment codes to simplify the process of sharing payment information.

Restore OP Codes, May 2019

 Bitcoin ABC | nChain

Re-activate the following additional opcodes: OP_MUL, OP_LSHIFT, OP_RSHIFT, and OP_INVERT.

Enable Schnorr signatures

 Bitcoin ABC

Schnorr signatures are provably non-malleable and have the remarkable property that multiple parties can collaborate to produce a signature that is valid for the sum of their public keys. This is the building block for various higher-level constructions that improve efficiency and privacy, such as multisignatures and others.

Enforce minimal pushdata

 Bitcoin ABC

As per existing standardness checks, enforce that all pushed data is a minimal representation at the script layer.

Enforce NULLDUMMY (BIP 147)

 Bitcoin ABC

As per BIP 147, enforce that the dummy element in OP_CHECKMULSIG(VERIFY) is a null stack element. This will go into effect at the consensus layer.

Allow <100 byte txs except those of 64 bytes

 Bitcoin ABC

This rule prevents a hash griding attack, where SPV wallets can confuse a 64 byte transaction for a merkle node. The amount of entropy in each 32-byte sections of the transaction is insufficient to prevent a preimage attack. In this case, a valid transaction could be found with a hash equal to the first, or last, 32 bytes of a 64-byte transaction.

CompactBlocks

 Bitcoin Unlimited

Supporting CB in BU would strengthen the connections between the BU peers and the rest of the network, without having to rely on intermediates.

Graphene v2

 Bitcoin Unlimited

Introduce a set of improvements (phase 1) and extensions (phase 2) to improve both the performance and functionality of the Graphene block relay protocol.

Xthinner

 Electron Cash

Improved xthin that leverages canonical block ordering.

CashShuffle

 Electron Cash

CashShuffle is a protocol for allowing users to combine their transactions with others, creating obfuscation. It builds upon CoinShuffle and adds a matching service. As such, it is a more complete and usable protocol.

Base32 addresses

 Bitcoin ABC | Bitcoin XT | Copay (Bitpay)

Support Base32 address format

Revised DAA

 Bitcoin ABC | Bitcoin XT

Revise Difficulty Adjustment Algorithm

Graphene v1

 Bitcoin Unlimited

An efficient method of announcing new blocks.

Re-enable Satoshi Opcodes

 Bitcoin ABC | nChain

Re-enable the previously disabled opcodes which were part of the original Bitcoin design. This should enable smart contract compilers, and a variety of functionality on Bitcoin Cash.

Default to 32MB blocks

 Bitcoin ABC

Start accepting blocks up to 32MB by default.

Increase default datacarriersize to 220 bytes

 Bitcoin ABC

To disincentivize the use of other methods to embed data into the chain, in particular via P2SH, the default datacarriersize is raised from 80 byte to 220 bytes, so it becomes the "cheapest" way of embedding data into the chain.

Double spend proof creation and forwarding

 Bitcoin Unlimited

Update to inform other nodes of double spend attempts immediately to improve the reliability of 0-conf transactions.

Canonical Transaction Ordering

 Bitcoin ABC | Bitcoin XT

With the exception of the coinbase transaction, transactions within a block must be sorted in numerically ascending order of the transaction id. This proposal is also known as Lexical Transaction Order. It simultaneously removes the existing Topological Transaction Order constraint.

Enforce minimum transaction size

 Bitcoin ABC

Transactions that are smaller than 100 bytes shall be considered invalid. This protects against a Merkle tree vulnerability that allows attackers to spoof transactions against SPV wallets.

Enforce Push-Only for scriptSig

 Bitcoin ABC

Transactions shall be considered invalid if an opcode with number greater than 96 (hex encoding 0x60) appears in a scriptSig.

Generalized version bits voting (BIP 135)

 Bitcoin Unlimited

BIP 135 extends the semantics of the signaling bits to cover arbitrary consensus changes, referred to under the general term 'forks'. The same range of version bits is used for signaling.

OP_CHECKDATASIG

 Bitcoin Unlimited | Bitcoin ABC

OP_CHECKDATASIG and OP_CHECKDATASIGVERIFY check whether a signature is valid with respect to a message and a public key. OP_CHECKDATASIG permits data to be imported into a script, and have its validity checked against some signing authority such as an "Oracle".

Clean Stack

 Bitcoin ABC

For a transaction to be valid, only a single non-zero item must remain on the stack upon completion of Script evaluation. If any extra data elements remain on the stack, the script evaluates to false. This is the same as BIP 62 rule #6.

XVersionMessage

 Bitcoin Unlimited

BCH node extended version and configuration fields for transporting a generic key-value map that is meant to hold the configuration and version parameters to communicate capabilities with other nodes (such as transmission protocols like Graphene).