Provable Data Possession (PDP) enables users to verify the integrity of outsourced data without full retrieval. To enhance reliability, users often store multiple data replicas on a single cloud, which creates a single point of failure. Existing PDP schemes also rely heavily on Public Key Infrastructure (PKI), posing key management and leakage risks—especially when clients handle private keys insecurely. A compromised key allows malicious cloud providers to forge proofs and hide data loss. To overcome these limitations, we propose IDKIMC-PDP, an identity-based, key-insulated PDP scheme supporting multi-copy storage across multiple clouds. It eliminates the need for certificate management and ensures data availability even if some replicas are corrupted. The scheme incorporates key insulation for forward and backward security, and its security is formally proven under standard assumptions. Analysis shows strong resistance to key leakage and forgery, while experiments confirm IDKIMC-PDP’s superior efficiency over existing multi-cloud PDP approaches.