113 - Median time-past as endpoint for lock-time calculations
BIP: 113 source Layer: Consensus (soft fork) Title: Median time-past as endpoint for lock-time calculations Authors: Thomas Kerin Mark Friedenbach Status: Deployed Type: Specification Assigned: 2015-08-10 License: PD Table of ContentsAbstractMotivationSpecificationDeploymentAcknowledgementsCompatibilityReferencesCopyright Abstract This BIP is a proposal to redefine the semantics used in determining a time-locked transaction's eligibility for inclusion in a block. The median of the last 11 blocks is used instead of the block's timestamp, ensuring that it increases monotonically with each block. Motivation At present, transactions are excluded from inclusion in a block if the present time or block height is less than or equal to that specified in the locktime. Since the consensus rules do not mandate strict ordering of block timestamps, this has the unfortunate outcome of creating a perverse incentive for miners to lie about the time of their blocks in orde...
116 - MERKLEBRANCHVERIFY
BIP: 116 source Layer: Consensus (soft fork) Title: MERKLEBRANCHVERIFY Authors: Mark Friedenbach Kalle Alm BtcDrak Status: Draft Type: Specification Assigned: 2017-08-25 License: CC-BY-SA-4.0 License-Code: MIT Table of ContentsAbstractCopyrightSpecificationMotivationRationaleApplications1-of-N for large NHoneypotsImplementationDeploymentCompatibilityReferences Abstract A general approach to bitcoin contracts is to fully enumerate the possible spending conditions and then program verification of these conditions into a single script. At redemption, the spending condition used is explicitly selected, e.g. by pushing a value on the witness stack that cascades through a series of if/else constructs. This approach has significant downsides, such as requiring all program pathways to be visible in the scriptPubKey or redeem script, even those which are not used at validation. This wastes space on the block chain, restricts the size of possible scripts ...
68 - Relative lock-time using consensus-enforced sequence numbers
BIP: 68 source Layer: Consensus (soft fork) Title: Relative lock-time using consensus-enforced sequence numbers Authors: Mark Friedenbach BtcDrak Nicolas Dorier kinoshitajona Status: Deployed Type: Specification Assigned: 2015-05-28 Table of ContentsAbstractMotivationSpecificationImplementationAcknowledgmentsDeploymentCompatibilityReferences Abstract This BIP introduces relative lock-time (RLT) consensus-enforced semantics of the sequence number field to enable a signed transaction input to remain invalid for a defined period of time after confirmation of its corresponding outpoint. Motivation Bitcoin transactions have a sequence number field for each input. The original idea appears to have been that a transaction in the mempool would be replaced by using the same input with a higher sequence value. Although this was not properly implemented, it assumes miners would prefer higher sequence numbers even if the lower ones were more profi...
117 - Tail Call Execution Semantics
BIP: 117 source Layer: Consensus (soft fork) Title: Tail Call Execution Semantics Authors: Mark Friedenbach Kalle Alm BtcDrak Status: Draft Type: Specification Assigned: 2017-08-25 License: CC-BY-SA-4.0 License-Code: MIT Table of ContentsAbstractCopyrightSpecificationMotivationRationaleGeneralized MASTComparison with BIP114ImplementationDeploymentCompatibilityReferences Abstract BIP16 (Pay to Script Hash)[1] and BIP141 (Segregated Witness)[2] provide mechanisms by which script policy can be revealed at spend time as part of the execution witness. In both cases only a single script can be committed to by the construct. While useful for achieving the goals of these proposals, they still require that all policies be specified within the confine of a single script, regardless of whether the policies are needed at the time of spend. This BIP, in conjunction with BIP116 (MERKLEBRANCHVERIFY)[3] allows for a script to commit to a practically unbounded n...
112 - CHECKSEQUENCEVERIFY
BIP: 112 source Layer: Consensus (soft fork) Title: CHECKSEQUENCEVERIFY Authors: BtcDrak Mark Friedenbach Eric Lombrozo Status: Deployed Type: Specification Assigned: 2015-08-10 License: PD Table of ContentsAbstractSummaryMotivationContracts With Expiration DeadlinesEscrow with TimeoutRetroactive InvalidationHash Time-Locked ContractsBidirectional Payment ChannelsLightning Network2-Way Pegged SidechainsSpecificationReference ImplementationDeploymentCreditsReferencesCopyright Abstract This BIP describes a new opcode (CHECKSEQUENCEVERIFY) for the Bitcoin scripting system that in combination with BIP 68 allows execution pathways of a script to be restricted based on the age of the output being spent. Summary CHECKSEQUENCEVERIFY redefines the existing NOP3 opcode. When executed, if any of the following conditions are true, the script interpreter will terminate with an error: the stack is empty; orthe top item on the stack is less than 0; ort...
98 - Fast Merkle Trees
BIP: 98 source Layer: Consensus (soft fork) Title: Fast Merkle Trees Authors: Mark Friedenbach Kalle Alm BtcDrak Status: Draft Type: Specification Assigned: 2017-08-24 License: CC-BY-SA-4.0 License-Code: MIT Table of ContentsAbstractCopyrightMotivationSpecificationRationaleInclusion ProofsExampleRationaleFast Merkle ListsImplementationDeploymentCompatibilityReferences Abstract In many applications it is useful to prove membership of a data element in a set without having to reveal the entire contents of that set. The Merkle hash-tree, where inner/non-leaf nodes are labeled with the hash of the labels or values of its children, is a cryptographic tool that achieves this goal. Bitcoin uses a Merkle hash-tree construct for committing the transactions of a block into the block header. This particular design, created by Satoshi, suffers from a serious flaw related to duplicate entries documented in the National Vulnerability Database as CVE-2012-245...
123 - BIP Classification
BIP: 123 source Title: BIP Classification Authors: Eric Lombrozo Status: Deployed Type: Process Assigned: 2015-08-26 License: CC0-1.0 OR FSFAP Table of ContentsAbstractCopyrightMotivationSpecification1. Consensus LayerSoft ForksHard Forks2. Peer Services Layer3. API/RPC Layer4. Applications LayerClassification of existing BIPs Abstract This document describes a classification scheme for BIPs. BIPs are classified by system layers with lower numbered layers involving more intricate interoperability requirements. The specification defines the layers and sets forth specific criteria for deciding to which layer a particular standards BIP belongs. Copyright This BIP is dual-licensed under the Creative Commons CC0 1.0 Universal and FSF All Permissive licenses. Motivation Bitcoin is a system involving a number of different standards. Some standards are absolute requirements for interoperability while others can be considered optional, giving implementers a choice of whether to su...