# kaal:claim:3782198-029

**Claim.** A blockchain is immutable because any attempt to edit an old block changes the hash of that information and is immediately rejected by the network that follows the protocol.

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

**Holds when.**

- holds as long as the network keeps following the blockchain protocol

**Source quote.**

> The blockchain is immutable, because any attempt to edit the old blocks will be immediately rejected by the network. A single number or letter changed anywhere in its entire history will result in a different hash of the information.

**From.** Craig Calcaterra, Wulf A. Kaal, *Contemporary Decentralization* (2021), New tools: blockchain protocols, page 29

**Cite as.** Craig Calcaterra, Wulf A. Kaal, Contemporary Decentralization (2021). SSRN: https://ssrn.com/abstract=3782198

**Verify.** sha256 of source PDF `e7e1378e3eed06cace6534e7792a7307d607d18bc6beb4ac45896476280728e4` at https://raw.githubusercontent.com/wulfkaal/Academic-Papers/main/papers/pdf/Calcaterra%20and%20Kaal%20-%202021%20-%20Contemporary%20Decentralization.pdf

**Topics.** blockchain, consensus-and-security

**Keywords.** immutability, hash-functions, blockchain, security

**Related claims.**

- restates: https://wulfkaal.github.io/claims/3071378-005

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