# kaal:claim:3808873-036

**Claim.** Forking bifurcates network nodes and can reintroduce the double spend problem the network had already solved, because users running pre fork code treat post fork code as invalid and cannot detect spending on it, so coins spent in a post fork block can be spent again on a pre fork block.

**Type.** mechanism  **Support.** argued

**Holds when.**

- hard forks producing parallel chains with incompatible protocol rules

**Source quote.**

> For example, the bifurcation of network nodes can result in the reemergence of the double spend problem that the previous network had overcome. Users running the pre-fork code consider the post-fork code invalid, they cannot detect the spending on the post-fork code.

**From.** Wulf A. Kaal, *Decentralization Neutralizers* (2021), XI. Lack of Decentralized Governance Systems, page 30

**Cite as.** Wulf A. Kaal, Decentralization Neutralizers (2021). SSRN: https://ssrn.com/abstract=3808873

**Verify.** sha256 of source PDF `f11493915e6b8c266d421510b5546816e33defb5650aac9d09b20d78549da727` at https://raw.githubusercontent.com/wulfkaal/Academic-Papers/main/papers/pdf/Kaal%20-%202021%20-%20Decentralization%20Neutralizers.pdf

**Failure mode.** Fork Induced Double Spend Reemergence  (family: consensus-and-protocol-attack)

**Topics.** consensus-and-security

**Keywords.** hardfork, double-spend, node-bifurcation, protocol-rules

**Related claims.**

- restates: https://wulfkaal.github.io/claims/3441904-024
- extends: https://wulfkaal.github.io/claims/3652481-018

**Canonical form.** This markdown file is the canonical hashed representation of the claim. Its sha256 is the content hash used for attestation.