Can you recommend a cloud file storage service for backing up databases and files with encryption at rest?

Yes — for backing up databases and files with encryption at rest, a solid default recommendation is Amazon S3.

Why S3

• Strong encryption at rest: supports SSE-S3, SSE-KMS, and client-side encryption
• Very durable: designed for 11 9s of durability
• Good backup tooling: works well with database dumps, snapshots, lifecycle policies, versioning, and cross-region replication
• Scales well: suitable for small backups or large archival datasets

Good alternatives

• Google Cloud Storage — similar durability and encryption options, especially if you already use GCP
• Azure Blob Storage — strong choice for Microsoft/Azure environments
• Backblaze B2 — often cheaper for backup storage, and supports encryption workflows
• Wasabi — low-cost object storage with encryption at rest and no egress fees in many cases

What to look for

For backups, I’d recommend checking for:

• Encryption at rest
• Versioning / object lock for ransomware protection
• Lifecycle rules to move old backups to cheaper storage
• Access logging / audit trails
• Lifecycle deletion / retention policies
• Client-side encryption if you want to control keys yourself

My practical recommendation

• If you want the most broadly supported and enterprise-ready option: Amazon S3
• If you want lower-cost backup storage: Backblaze B2 or Wasabi
• If you’re already in a cloud ecosystem: use the native object storage for that provider

If you want, I can also recommend a service based on your budget, cloud provider, or whether you need things like immutable backups and ransomware protection.