Encrypt a file using KMS and push to S3

Question

I have a AWS lambda function written in Python that needs to create a file using data in a string variable , KMS encrypt the file and push the file to S3.

s3_resource = boto3.resource("s3")
s3_resource.Bucket(bucket_name).put_object(Key=s3_path, Body=data)

I am using the above to create the file in S3 , but is there a way to use the KMS keys that I have to encrypt the file while pushing to S3 ?

Answer 1

To use KMS encryption when adding an object use the server side encryption options:

• ServerSideEncryption ="aws:kms" - to enable KMS encryption
• SSEKMSKeyId=keyId - to specify the KMS key you want to use for encryption. If you don't specify this, AWS will just use your default account key.

For example:

s3_resource.Bucket(bucket_name).put_object(
        Key=s3_path,
        Body=data,
        ServerSideEncryption ="aws:kms"
    )

You may also need to enable v4 signing in your boto configuration file.