You click Delete and your data is gone…..or is it? The IT infrastructure and services you use will not remove it straight away as you may need to recover it if the deletion was accidental, or it may need to be retained to meet legal requirements.
For Google users, there are details of their four stage process to remove data
Stage 1 – Deletion request; this is usually by a user but can be by Google when you delete your Google account.
Stage 2 – Soft deletion; once the deletion request is made, data is typically marked for deletion immediately, the goal is to perform this step within a maximum period of 24 hours. At this stage data is no longer available but can be recovered. The recovery period can be up to 30 days.
Stage 3 – Logical deletion from active systems; after the recovery period has ended data is deleted successively from Google’s active and backup storage systems by being overwritten over time or cryptographic erasure (this renders data unreadable by deleting the encryption keys needed to decrypt that data).
Stage 4 – Expiration from backup systems; deleted data is eliminated from backup systems using overwriting and cryptographic techniques.
Google has produced a diagram that shows the timelines for the different stages.