Transaction Malleability

Definition ∞ Transaction malleability is a vulnerability where certain non-essential parts of a transaction’s digital signature can be altered before it is confirmed on a blockchain. This alteration changes the transaction’s unique identifier without invalidating the transaction itself. While not directly allowing funds to be stolen, it can disrupt systems that rely on consistent transaction identifiers, potentially causing issues with tracking or confirming payments. Bitcoin experienced this issue in its early days.
Context ∞ Transaction malleability was a significant technical concern in early cryptocurrency development, particularly with Bitcoin, and is often mentioned in historical or technical news discussions. While largely addressed in many modern blockchain protocols, especially with the implementation of Segregated Witness, it remains a relevant concept for understanding blockchain security evolution. Future protocol upgrades continue to prioritize transaction integrity and resistance to similar vulnerabilities.