How to encrypt your object in S3

To encrypt your objects in Amazon S3, you have several options:

1. Server-Side Encryption with Amazon S3 Managed Keys (SSE-S3): This is the default encryption method for all new objects uploaded to S3 as of January 5, 2023. It's applied automatically at no additional cost and with no performance impact. You don't need to do anything extra for this base level of encryption.

2. Server-Side Encryption with AWS Key Management Service (SSE-KMS): To use this method, add the 'x-amz-server-side-encryption' header with the value 'aws:kms' to your S3 API requests when uploading objects.

3. Server-Side Encryption with Customer-Provided Keys (SSE-C): For this method, set the 'x-amz-server-side-encryption' header to 'True' or 'False' in your S3 API requests.

4. Client-Side Encryption: You can also encrypt objects on the client-side before uploading to S3. The Amazon S3 Encryption Client can help with this process.

To specify SSE-S3 encryption when uploading an object using the AWS CLI, you can use a command like this:

aws s3api put-object --bucket your-bucket-name --key your-object-key --server-side-encryption AES256 --body path/to/your/file

For more advanced scenarios, you can use the Amazon S3 Encryption Client. This allows you to create a keyring with a KMS key as your wrapping key, and then use the PutObject method to encrypt and upload your object. You can also include an optional encryption context for additional security.

Remember, it's a best practice to implement bucket policies that require encryption for all uploaded objects and to only allow encrypted connections over HTTPS (TLS) to your S3 buckets.
Sources
Encryption best practices for Amazon S3 - AWS Prescriptive Guidance
Specifying server-side encryption with Amazon S3 managed keys (SSE-S3) - Amazon Simple Storage Service
Amazon S3 Encryption Client for Go examples - Amazon S3 Encryption Client

Hello Mahendra,

Amazon S3 provides three types of server-side encryption:

• SSE-S3 (AES-256): Uses S3-managed keys.
• SSE-KMS: Uses AWS Key Management Service (KMS) keys.
• Dual-layer server-side encryption with AWS Key Management Service keys (DSSE-KMS).

1. SSE-S3 (AES-256) – S3-Managed Keys: With Server-Side Encryption with S3-managed keys (SSE-S3), AWS automatically encrypts your objects using the AES-256 encryption algorithm. S3 manages the encryption keys, so you don’t need to configure or maintain them. This is the simplest encryption method and is enabled by adding --sse AES256 when uploading objects.

2. SSE-KMS – AWS KMS-Managed Keys: Server-Side Encryption with AWS KMS (SSE-KMS) integrates S3 with AWS Key Management Service (KMS) to provide additional security. You can use either an AWS-managed KMS key or a customer-managed key for encryption. This method gives you fine-grained access control, audit logs, and key rotation capabilities. It is enabled using --sse aws:kms --sse-kms-key-id <KMS_KEY_ID>.

3. Dual-layer server-side encryption with AWS Key Management Service keys (DSSE-KMS): Dual-layer server-side encryption with AWS Key Management Service (DSSE-KMS) provides two independent layers of encryption for objects stored in Amazon S3. This feature is designed for workloads with strict compliance and regulatory requirements, ensuring that even if one encryption layer is compromised, the data remains protected by a second independent layer.

Reference: https://docs.aws.amazon.com/AmazonS3/latest/userguide/UsingEncryption.html

Thank you

AWS encrypts the objects after uploading them to S3 and decrypts them when you download them.

1.Using SSE-S3 (AES-256) This is the simplest option where AWS manages the encryption keys. steps:

1. Go to the S3 Console.
2. Select the Bucket where you want to upload the object.
3. Click Upload → Add files.
4. Under Properties, go to Server-side encryption.
5. Select Amazon S3-managed keys (SSE-S3).
6. Click Upload.

or AWS CLI aws s3 cp myfile.txt s3://my-bucket/ --sse AES256

Method 2: Client-Side Encryption (CSE) You encrypt data before uploading it to S3, and AWS has no access to your keys.

Using SSE-KMS (AWS Key Management Service) AWS manages the keys, but you control permissions using AWS KMS.

Via AWS Console Follow the same steps as SSE-S3. In the Server-side encryption section, choose AWS Key Management Service (AWS KMS). Select a KMS key (default or custom). Click Upload.

Best Practices

• Enable default encryption for your S3 bucket.
• Use SSE-KMS for better key management and auditing.
• Apply bucket policies to enforce encryption.
• Rotate KMS keys periodically for better security.
• if handling highly sensitive data, use Client-Side Encryption.