Cloud computing is one of the most holistically used technology nowadays. To do the forensics in the cloud, it is essential to accumulate as well as safeguard the justifiable facts of different events to find out the culprit. However, logging the events that take place in the cloud and securing them while preserving the privacy of cloud consumers is a big challenge. Currently, cloud consumers are relying on cloud service providers to get the logs of events that take place on their data despite multi-stakeholder collusion. Thus, there is a strong requirement of publicly verifiable secure logging which will play a vital role in criminal investigations without depending on a third party. In this paper, we developed a Blockchain-driven Secure Logging-as-a-Service (BlockSLaaS) scheme that supports, privacy-preserving secure logging and eclectic verification. To make a serene forensic investigation, the proposed scheme guarantees the trustworthiness and reclamation of logs in case of tampering. The scheme proposes integrating the Interplanetary File System (IPFS), a decentralized off-chain data storage platform with blockchain for efficient logging and its visualization. The extensive experiments on the number of transactions, storage requirement, uploading, reading, and downloading of log files for varying node count and file size are performed. The proposed method is compared with nine existing methods based on 9 security and performance features. The response, proof insertion, and proof-verification times of the proposed BlockSLaaS are 38.3, 29.7, and 26.3 milliseconds respectively which outperform the existing methods.