## 4 Approaches of Migration Processes  
There are different approaches in which the authors analyze and define migration processes or recommend guides of migration to Cloud computing. Reference [24] defines a set of points to consider when making the decision to migrate a project to an external cloud, which are as follows: (1) Look for an established vendor with a track record; (2) Does the project really need to be migrated?; (3) Consider data security; (4) Data transfer; (5) Data storage and location; (6) Scaling; (7) Service level guarantees; (8) Upgrade and maintenance schedules; (9) Software architecture; and (10) Check with the lawyers. Other important steps, shown in [25] that can be taken in preparation for Cloud computing adoption are: (i) Identify all potential opportunities for switching from existing computing arrangements to cloud services; (ii) Ensure that in-house infrastructure complements cloud-based services; (iii) Develop a cost/benefit and risk evaluation framework to support decisions about where, when, and how cloud services can be adopted; (iv) Develop a roadmap for optimizing the current ICT environment for adoption of public and/or private cloud services; (v) Identify which data cannot be held in public Cloud computing environments for legal and/or risk-mitigation reasons; (vi) Identify and secure in-house competencies that will be required to manage effective adoption of cloud services; (vii) Designate a cross-functional team to continually monitor which new services, providers, and standards are in this space, and to determine if they affect the roadmap; (viii) Evaluate technical challenges that must be addressed when moving any current information or applications into a cloud environment; (ix) Ensure that the networking environment is ready for Cloud computing. Reference [26] defines the points to take into account in the migration such as (i) Deciding on the applications and data to be migrated; (ii) Risk mitigation; (iii) Understanding the costs; (iv) Making sure the regulatory things are handled; (v) Training the developers and staff. A phased strategy for migration is presented in [27] where the author describe a step by step guide with six steps given as such; (1) Cloud Assessment Phase; (2) Proof of Concept Phase; (3) Data Migration Phase; (4) Application Migration Phase; (5) Leverage of the Cloud; (6) Optimization Phase. In this strategy some security aspects are indicated and some correct security best practices are defined such as safeguard of credentials, restricting users to resources, protecting your data by encrypting it at-rest (AES) and in-transit (SSL) or adopting a recovery strategy. The alternative migration strategies which [PERSON] [28] suggests IT organizations should consider are: (i) Rehost, _i.e._, redeploy applications to a different hardware environment and change the application's infrastructure configuration; (ii) Refactor, _i.e._, run applications on a cloud provider's infrastructure; (iii) Revise, _i.e._, modify or extend the existing code base to support legacy modernization requirements, then use rehost or refactor options to deploy to cloud; (iv) Rebuild, _i.e._, Rebuild the solution on PaaS, discard code for an existing application and re-architect the application; (v) Replace, _i.e._, discard an existing application (or set of applications) and use commercial software delivered as a service.  
As we can see, the approaches of migration process identify and define a set of steps or points to follow and consider in the migration to Cloud which can be used for our propose of migrating security aspects to Cloud, but the initiatives do not consider security or only specific security aspects that do not guarantee a full migration process of all security features of the legacy systems and it is this aspect which we want to achieve.