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LibraryInteroperability2022Design paperCorpus record

Cross-Consensus Messaging: Polkadot's message format

XCM. Parity and Web3 Foundation.

XCM is a message format between consensus systems in the Polkadot line. It is not a bridge to Ethereum, and it is not the Polkadot white paper's security argument restated.

A reading of the project's public design document. Not a copy, not a benchmark, and not an offer.

XCM is a message format between consensus systems in the Polkadot line. It is not a bridge to Ethereum, and it is not the Polkadot white paper's security argument restated.
Evidence
Primary paper
Re-measured
No
Assumptions
3
Records linked
6

01 Claim ledger

What the paper is allowed to say

Each row is a sentence already in the study. The status is the same on every row: a model claim, not a live measurement.

  1. Claim 01 · Paper model

    The defect

    A message format does not, by itself, verify the sender. The transport, whether a relay chain or a channel, is the security.

  2. Claim 02 · Paper model

    The proposal

    XCM is a message format between consensus systems in the Polkadot line. It is not a bridge to Ethereum, and it is not the Polkadot white paper's security argument restated.

  3. Claim 03 · Paper model

    The mechanism

    An XCM programme describes what to do: withdraw, deposit, transact. The programme is not a proof.

  4. Claim 04 · Paper model

    The bound

    This note does not say XCM is safe across arbitrary chains.

02 Three cuts

Observation, model, falsifier

A desk does not stop at the summary. Each claim is cut three ways, using only this study's own assumptions and checks. Nothing here is a new figure.

  1. 01 The defect

    Observation

    What the study says

    A message format does not, by itself, verify the sender. The transport, whether a relay chain or a channel, is the security.

    Model

    What has to hold

    You are reading Polkadot's XCM documentation. IBC is a different interop design.

    Falsifier

    What would retire it

    What transport authenticates the sender?

  2. 02 The proposal

    Observation

    What the study says

    XCM is a message format between consensus systems in the Polkadot line. It is not a bridge to Ethereum, and it is not the Polkadot white paper's security argument restated.

    Model

    What has to hold

    You are reading Polkadot's XCM documentation. IBC is a different interop design.

    Falsifier

    What would retire it

    What transport authenticates the sender?

  3. 03 The mechanism

    Observation

    What the study says

    An XCM programme describes what to do: withdraw, deposit, transact. The programme is not a proof.

    Model

    What has to hold

    No price, supply, yield, or adoption figure is added by this desk.

    Falsifier

    What would retire it

    What happens to an asset if an instruction fails halfway?

  4. 04 The bound

    Observation

    What the study says

    This note does not say XCM is safe across arbitrary chains.

    Model

    What has to hold

    You are reading Polkadot's XCM documentation. IBC is a different interop design.

    Falsifier

    What would retire it

    Which version of XCM is the runtime using?

03 Sequence

One action, as an operating tape

  1. 01An XCM programme describes what to do: withdraw, deposit, transact. The programme is not a proof.
  2. 02The transport that delivers it decides whether the sender is who they claim. Citing XCM without the transport cites a language.
  3. 03Versioned instructions mean two runtimes can disagree. The version is part of the citation.

04 Load-bearing

The argument, and where a pitch drops it

  1. What the name has to mean

    The cut

    XCM is a message format between consensus systems in the Polkadot line. It is not a bridge to Ethereum, and it is not the Polkadot white paper's security argument restated.

    Why it carries weight

    If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.

    Where it is dropped

    The Polkadot paper is a different study.

  2. What actually moves

    The cut

    The transport that delivers it decides whether the sender is who they claim. Citing XCM without the transport cites a language.

    Why it carries weight

    If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.

    Where it is dropped

    A later client, parameter or reward formula is a different object from this paragraph.

  3. What a later deployment may change

    The cut

    Versioned instructions mean two runtimes can disagree. The version is part of the citation.

    Why it carries weight

    If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.

    Where it is dropped

    A later client, parameter or reward formula is a different object from this paragraph.

05 Register

What has to be true

  • Model · Not re-measured

    You are reading Polkadot's XCM documentation. IBC is a different interop design.

  • Model · Not re-measured

    The document is the one at the source URL. A marketing page with the same brand is not this text.

  • Model · Not re-measured

    No price, supply, yield, or adoption figure is added by this desk.

06 Divergence

What happened after the paper

A failed instruction can trap assets. The trap rule is part of the design and is not a fee.

A later client, parameter set, or reward formula is a different object. Cite this paper for the mechanism. Cite a primary release for the network. This desk has not re-run the proof.

07 Pre-mortem

What to check before you use the idea

  4. 0 of 3 marked on this browser. A mark is a reading note, not a pass, a rating, or a recommendation.

08 Anatomy

The paper, in the order a builder needs

The problem it names

A message format does not, by itself, verify the sender. The transport, whether a relay chain or a channel, is the security.

What the design proposes

  • An XCM programme describes what to do: withdraw, deposit, transact. The programme is not a proof.
  • The transport that delivers it decides whether the sender is who they claim. Citing XCM without the transport cites a language.
  • Versioned instructions mean two runtimes can disagree. The version is part of the citation.

How the mechanism is specified

  • An XCM programme describes what to do: withdraw, deposit, transact. The programme is not a proof.
  • The transport that delivers it decides whether the sender is who they claim. Citing XCM without the transport cites a language.
  • Versioned instructions mean two runtimes can disagree. The version is part of the citation.

What this page does not treat as proven

  • This note does not say XCM is safe across arbitrary chains.
  • The Polkadot paper is a different study.
  • A failed instruction can trap assets. The trap rule is part of the design and is not a fee.

Why the desk still reads it

XCM is a message format between consensus systems in the Polkadot line. It is not a bridge to Ethereum, and it is not the Polkadot white paper's security argument restated.

09 Lexicon

Terms, opened into the record

XCM
A programme of instructions between consensus systems. It is not a light client.
Transport
The channel that authenticates the message. The format does not replace it.

10 Repository

Every linked record on this page

Underlined words open a page that already exists: a concept, a protocol profile, a failure record, or another paper. If a word is not underlined, this desk does not have a record for it.

Papers

This is Blockchain Lab's reading of a public design paper. It is not the paper, not a copy of it, and not an offer of tokens, equity, custody or a partnership. Later network behaviour can diverge from the text. Nothing here is investment, legal or technical advice.

Research status: Design paper. Last reviewed: 1 October 2026. This is a reading of a public paper, not investment, legal or security advice.