Amazon S3 | Object Encryption.

 

twtech clear overview of Amazon S3 Object Encryption – how it works, the different options available, and how to choose the right one based on twtech use cases and compliance requirements.

 Amazon S3: Object Encryption Overview

Amazon S3 offers encryption at rest and in transit:

 Encryption at Rest

This protects data when it is stored on disk within AWS data centers.

 Encryption in Transit

Use HTTPS (SSL/TLS) when uploading/downloading to protect data in transit.

Types of S3 Object Encryption

Encryption Type	Description	Managed By	Key Type
SSE-S3 (AES-256)	Server-side encryption with S3-managed keys	AWS	Implicit AES-256
SSE-KMS	Server-side encryption with AWS KMS customer-managed keys	AWS + twtech	AWS KMS key (CMK)
SSE-C	Server-side encryption with customer-provided keys	twtech	External key (not stored in AWS)
Client-Side Encryption	twtech encrypt the data before uploading	twtech	the custom keys

 1. SSE-S3 (Amazon S3-Managed Keys)

• Simple to use: just enable default encryption.
• Uses AES-256 automatically.
• No KMS involvement, so no extra cost.
• Minimal control, limited audit logging.

# bash

aws s3 cp twtech-file.txt s3://twtech-s3bucket-name/ --sse AES256

 2. SSE-KMS (AWS KMS-Managed Keys)

• Uses AWS Key Management Service (KMS).
• Allows control over who can access data via IAM + KMS key policies.
• Supports audit logging via AWS CloudTrail.
• Required for compliance in many regulated industries.
• Extra cost for KMS requests.

# bash

aws s3 cp twtech-file.txt s3://twtec-s3bucket-name/ --sse aws:kms --sse-kms-key-id alias/twtech-key 

 3. SSE-C (Customer-Provided Keys)

• twtech provides its own key during each upload/download.
• S3 does not store the key — twtech must manage it.
• Useful for ultra-sensitive data, but operationally complex.
• No support for S3 replication or lifecycle rules.

 4. Client-Side Encryption

• twtech encrypt the object before uploading.
• Use twtech own encryption library or AWS SDK’s encryption client.
• S3 stores only the encrypted data.
• Full control, but twtech manage key rotation, key storage, and decryption logic.

 How twtech Enables Default Encryption (SSE-S3 or SSE-KMS)

• Go to S3 Console → Bucket → Properties → Default Encryption
• Choose:
• AES-256 for SSE-S3
• aws:kms for SSE-KMS (optionally specify CMK)

 twtech Recommendation of When to Use What.

Use Case	Best Option
Simplicity, low cost	SSE-S3
Compliance, auditability, access control	SSE-KMS
twtech manage key lifecycle externally	SSE-C
Full client-side encryption required	Client-Side