In a cloud-based multiple client encryption and deduplication environment, secret plaintext data of a client is encrypted to produce ciphertext in an enclave comprising a trusted execution environment which is inaccessible by unauthorized entities and processes even with administrator privileges. Encryption is performed with an initialization vector and an encryption key calculated in the enclave. The encrypted ciphertext is deduplicated prior to storage by comparing a hash of the corresponding plaintext data to hashes of previously stored plaintext data.