A company needs to save confidential medical results in an Amazon S3 bucket.

Amazon S3 Object Lock is the AWS feature designed for WORM storage. AWS documentation says Object Lock helps prevent objects from being deleted or overwritten for a fixed amount of time or indefinitely and supports a WORM model. In compliance mode, even an administrator cannot shorten or remove the retention period before it expires, which is critical for confidential medical records and regulatory retention. Setting a 1-year retention period satisfies the minimum retention requirement, and IAM policies can still control which approved users are allowed to upload new objects. MFA Delete and ordinary IAM policies do not provide the same immutable WORM guarantees. A custom Lambda-based approach would add unnecessary complexity and still would not be the native compliance-oriented control that S3 Object Lock provides.

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