The Vcem Method for Verifying Cryptographic Key Destruction Using Zero-Knowledge Proofs

Cryptographic erasure can terminate access to encrypted data by destroying its key, but verifying a report of this operation requires a separate mechanism. This article specifies the Verifiable Cryptographic Erasure Method (VCEM), which combines data lifecycle management through the Smart Contract for Data Expiry (SCDE), a key-management system, and zero-knowledge proofs. The relation between public and private proof inputs binds a signed message to the object, retention policy, and request while hiding the internal key identifier and commitment randomness. The choice of Groth16 is justified, and circuit constraints are distinguished from smart-contract state checks. The prototype was evaluated in three configurations and for six object sizes using 1,800 measurements. In the local experimental environment, VCEM increased the mean end-to-end latency by approximately 0.50 s relative to the baseline SCDE procedure. Proof generation, verification, and transaction costs were evaluated separately. The results characterize the operation of the prototype and the cost of verifying a message from a trusted key-management component. Proof acceptance establishes the specified relation; it does not independently establish the destruction of all possible key copies.