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1. Nguyen et al. [2] present an evaluating and enforcing architecture for SLA agreements based on distributed ledgers. Their approach relies on keeping the SLA assessment procedure safe and unmodified due to blockchain immutability while utilizing an automated SLA monitoring and computation process that takes place within the blockchain infrastructure and guarantees the successful completion of the SLA evaluation with status acknowledgment for the end-user. However, their solution does not perceive the system in a whole decentralization model, neglecting the possibilities for fairer agreements in terms of transparency and privacy.
   
   Similar approaches are bounded by the same kind of models where the SLA intelligence lacks a holistic view, while privacy and transparency issues should be tackled. Ranchal and Choudhury [3] present an autonomous and trusted framework for unceasing SLA monitoring in multi-cloud ecosystems. In order to fairly detect SLA violations in a hierarchical system structure, their solution is aiming to address the SLA assessment procedure in a multilevel cloud environment with diverse regulations and laws. Furthermore, Alowayed et al. [4] propose a provider evaluation solution according to the providers’ commitments to their interconnection SLA agreements. Through a metric measurement mechanism the SLA scores are verified for each provider towards their on chain evaluation. By endorsing a privacy-preserving protocol for SLA agreements, it is pursued to objectively define the provider's SLA score and privately store it on chain in order for the interested end-user to access.
   
   
2. Other approaches suggest more focused solutions as far as the privacy of the blockchain participants is concerned, however, they still do not tackle entirely the on chain privacy of the user data from third blockchain parties. Uriarte et al. [5] present an SLA management framework that resolves the specification and enforcement of dynamic SLAs that track and define the service parameter which render SLAs changes over time. The proposed architecture manages to convert an SLA to its smart contract equivalent that dynamically unfolds service provisioning and sequentially generates objective measurements for the SLA assessment through a federation of monitoring entities. In similar research, Alzubaidi et al. [6] proposed on chain assessing SLA compliance and consequences enforcement through dependability validation. By employing a diagnostic accuracy method, trust is assumed in service providers in order to acknowledge SLA breach incidents and execute the corresponding compensations. 
   
   
3. Finally, other approaches try to address the related research area, however, they lack the kind of simplicity and utility in the system's workflow as far as the actor users participation is concerned. D’Angelo et al. [7] inspect the challenges for enforcing accountability in Cloud infrastructures where SLA violations form an important and usual circumstance while arguing that blockchains seem to establish a key contributor towards accountable Clouds. Also, Tan et al. [8] propose a novel performing and safe SLA model where the trust among the different actors are addressed through blockchain. There is a clear argument on lack of effective supervision for the third-parties that manage the monitoring and lack of efficient compensation mechanism on SLA violations. The presented model supervises the provider actors on the blockchain with dedicated smart contracts.

3. Architectural Approach

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