Securing leakage and collusion attacks on encrypted cloud storage using memorizable passwords

Abstract Encryption is the most direct technique to protect data confidentiality when users outsource their data to the cloud. Typically, ciphertexts are stored in the cloud, while cryptographic keys are managed by a key management server (KMS). However, this approach introduces new challenges in securely managing both keys and ciphertexts. Specifically, two crucial issues remain unresolved. One is that the simultaneous leakage of data encryption key and ciphertexts stored in cloud can directly