Replicating encrypted objects

By default, Amazon S3 doesn't replicate objects that are encrypted by using server-side encryption with AWS Key Management Service (AWS KMS) keys (SSE-KMS) or dual-layer server-side encryption with AWS KMS keys (DSSE-KMS). To replicate objects encrypted with SSE-KMS or DSS-KMS, you must modify the bucket replication configuration to tell Amazon S3 to replicate these objects. This example explains how to use the Amazon S3 console and the AWS Command Line Interface (AWS CLI) to change the bucket replication configuration to enable replicating encrypted objects.

For more information, see Replicating objects created with server-side encryption (SSE-C, SSE-S3, SSE-KMS, DSSE-KMS).

Note

When an S3 Bucket Key is enabled for the source or destination bucket, the encryption context will be the bucket's Amazon Resource Name (ARN), not the object's ARN. You must update your IAM policies to use the bucket ARN for the encryption context. For more information, see S3 Bucket Keys and replication.

Note

You can use multi-Region AWS KMS keys in Amazon S3. However, Amazon S3 currently treats multi-Region keys as though they were single-Region keys, and does not use the multi-Region features of the key. For more information, see Using multi-Region keys in AWS Key Management Service Developer Guide.

For step-by-step instructions, see Configuring replication for source and destination buckets owned by the same account. This topic provides instructions for setting a replication configuration when the buckets are owned by the same and different AWS accounts.

To replicate encrypted objects with the AWS CLI, you do the following:

Create source and destination buckets and enable versioning on these buckets.
Create an AWS Identity and Access Management (IAM) service role that gives Amazon S3 permission to replicate objects. The IAM role's permissions include the necessary permissions to replicate the encrypted objects.
Add a replication configuration to the source bucket. The replication configuration provides information related to replicating objects that are encrypted by using KMS keys.
Add encrypted objects to the source bucket.
Test the setup to confirm that your encrypted objects are being replicated to the destination bucket.

The following procedures walk you through this process.

To replicate server-side encrypted objects (AWS CLI)

In this example, you create both the DOC-EXAMPLE-SOURCE-BUCKET and DOC-EXAMPLE-DESTINATION-BUCKET buckets in the same AWS account. You also set a credentials profile for the AWS CLI. This example uses the profile name acctA.

For more information about setting credential profiles, see Named Profiles in the AWS Command Line Interface User Guide. To use the commands in this example, replace the user input placeholders with your own information.
Use the following commands to create the DOC-EXAMPLE-SOURCE-BUCKET bucket and enable versioning on it. The following example commands create the DOC-EXAMPLE-SOURCE-BUCKET bucket in the US East (N. Virginia) (us-east-1) Region.
```
aws s3api create-bucket \
--bucket DOC-EXAMPLE-SOURCE-BUCKET \
--region us-east-1 \
--profile acctA
```
```
aws s3api put-bucket-versioning \
--bucket DOC-EXAMPLE-SOURCE-BUCKET \
--versioning-configuration Status=Enabled \
--profile acctA
```
Use the following commands to create the DOC-EXAMPLE-DESTINATION-BUCKET bucket and enable versioning on it. The following example commands create the DOC-EXAMPLE-DESTINATION-BUCKET bucket in the US West (Oregon) (us-west-2) Region.

Note
To set up a replication configuration when both DOC-EXAMPLE-SOURCE-BUCKET and DOC-EXAMPLE-DESTINATION-BUCKET buckets are in the same AWS account, you use the same profile. In this example, we use acctA. To configure replication when the buckets are owned by different AWS accounts, you specify different profiles for each.
```
aws s3api create-bucket \
--bucket DOC-EXAMPLE-DESTINATION-BUCKET \
--region us-west-2 \
--create-bucket-configuration LocationConstraint=us-west-2 \
--profile acctA
```
```
aws s3api put-bucket-versioning \
--bucket DOC-EXAMPLE-DESTINATION-BUCKET \
--versioning-configuration Status=Enabled \
--profile acctA
```

Next, you create an IAM service role. You will specify this role in the replication configuration that you add to the DOC-EXAMPLE-SOURCE-BUCKET bucket later. Amazon S3 assumes this role to replicate objects on your behalf. You create an IAM role in two steps:

Create a service role.
Attach a permissions policy to the role.

To create an IAM service role, do the following:
1. Copy the following trust policy and save it to a file called s3-role-trust-policy-kmsobj.json in the current directory on your local computer. This policy grants Amazon S3 service principal permissions to assume the role so that Amazon S3 can perform tasks on your behalf.
```
{
   "Version":"2012-10-17",
   "Statement":[
      {
         "Effect":"Allow",
         "Principal":{
            "Service":"s3.amazonaws.com"
         },
         "Action":"sts:AssumeRole"
      }
   ]
}
```
2. Use the following command to create the role:
```
$ aws iam create-role \
--role-name replicationRolekmsobj \
--assume-role-policy-document file://s3-role-trust-policy-kmsobj.json  \
--profile acctA
```

Next, you attach a permissions policy to the role. This policy grants permissions for various Amazon S3 bucket and object actions.

Copy the following permissions policy and save it to a file named s3-role-permissions-policykmsobj.json in the current directory on your local computer. You will create an IAM role and attach the policy to it later.

Important

In the permissions policy, you specify the AWS KMS key IDs that will be used for encryption of the DOC-EXAMPLE-SOURCE-BUCKET and DOC-EXAMPLE-DESTINATION-BUCKET buckets. You must create two separate KMS keys for the DOC-EXAMPLE-SOURCE-BUCKET and DOC-EXAMPLE-DESTINATION-BUCKET buckets. AWS KMS keys are not shared outside the AWS Region in which they were created.


{
   "Version":"2012-10-17",
   "Statement":[
      {
         "Action":[
            "s3:ListBucket",
            "s3:GetReplicationConfiguration",
            "s3:GetObjectVersionForReplication",
            "s3:GetObjectVersionAcl",
            "s3:GetObjectVersionTagging"
         ],
         "Effect":"Allow",
         "Resource":[
            "arn:aws:s3:::DOC-EXAMPLE-SOURCE-BUCKET",
            "arn:aws:s3:::DOC-EXAMPLE-SOURCE-BUCKET/*"
         ]
      },
      {
         "Action":[
            "s3:ReplicateObject",
            "s3:ReplicateDelete",
            "s3:ReplicateTags"
         ],
         "Effect":"Allow",
         "Condition":{
            "StringLikeIfExists":{
               "s3:x-amz-server-side-encryption":[
                  "aws:kms",
                  "AES256",
                  "aws:kms:dsse"
               ],
               "s3:x-amz-server-side-encryption-aws-kms-key-id":[
                  "AWS KMS key IDs(in ARN format) to use for encrypting object replicas"  
               ]
            }
         },
         "Resource":"arn:aws:s3:::DOC-EXAMPLE-DESTINATION-BUCKET/*"
      },
      {
         "Action":[
            "kms:Decrypt"
         ],
         "Effect":"Allow",
         "Condition":{
            "StringLike":{
               "kms:ViaService":"s3.us-east-1.amazonaws.com",
               "kms:EncryptionContext:aws:s3:arn":[
                  "arn:aws:s3:::DOC-EXAMPLE-SOURCE-BUCKET/*"
               ]
            }
         },
         "Resource":[
            "AWS KMS key IDs(in ARN format) used to encrypt source objects." 
         ]
      },
      {
         "Action":[
            "kms:Encrypt"
         ],
         "Effect":"Allow",
         "Condition":{
            "StringLike":{
               "kms:ViaService":"s3.us-west-2.amazonaws.com",
               "kms:EncryptionContext:aws:s3:arn":[
                  "arn:aws:s3:::DOC-EXAMPLE-DESTINATION-BUCKET/*"
               ]
            }
         },
         "Resource":[
            "AWS KMS key IDs(in ARN format) to use for encrypting object replicas" 
         ]
      }
   ]
}

Create a policy and attach it to the role.


$ aws iam put-role-policy \
--role-name replicationRolekmsobj \
--policy-document file://s3-role-permissions-policykmsobj.json \
--policy-name replicationRolechangeownerPolicy \
--profile acctA

Next, add the following replication configuration to the DOC-EXAMPLE-SOURCE-BUCKET bucket. It tells Amazon S3 to replicate objects with the Tax/ prefix to the DOC-EXAMPLE-DESTINATION-BUCKET bucket.

Important

In the replication configuration, you specify the IAM role that Amazon S3 can assume. You can do this only if you have the iam:PassRole permission. The profile that you specify in the CLI command must have this permission. For more information, see Granting a user permissions to pass a role to an AWS service in the IAM User Guide.


 <ReplicationConfiguration>
  <Role>IAM-Role-ARN</Role>
  <Rule>
    <Priority>1</Priority>
    <DeleteMarkerReplication>
       <Status>Disabled</Status>
    </DeleteMarkerReplication>
    <Filter>
       <Prefix>Tax</Prefix>
    </Filter>
    <Status>Enabled</Status>
    <SourceSelectionCriteria>
      <SseKmsEncryptedObjects>
        <Status>Enabled</Status>
      </SseKmsEncryptedObjects>
    </SourceSelectionCriteria>
    <Destination>
      <Bucket>arn:aws:s3:::DOC-EXAMPLE-DESTINATION-BUCKET</Bucket>
      <EncryptionConfiguration>
        <ReplicaKmsKeyID>AWS KMS key IDs to use for encrypting object replicas</ReplicaKmsKeyID>
      </EncryptionConfiguration>
    </Destination>
  </Rule>
</ReplicationConfiguration>

To add a replication configuration to the DOC-EXAMPLE-SOURCE-BUCKET bucket, do the following:

The AWS CLI requires you to specify the replication configuration as JSON. Save the following JSON in a file (replication.json) in the current directory on your local computer.


{
   "Role":"IAM-Role-ARN",
   "Rules":[
      {
         "Status":"Enabled",
         "Priority":1,
         "DeleteMarkerReplication":{
            "Status":"Disabled"
         },
         "Filter":{
            "Prefix":"Tax"
         },
         "Destination":{
            "Bucket":"arn:aws:s3:::DOC-EXAMPLE-DESTINATION-BUCKET",
            "EncryptionConfiguration":{
               "ReplicaKmsKeyID":"AWS KMS key IDs (in ARN format) to use for encrypting object replicas"
            }
         },
         "SourceSelectionCriteria":{
            "SseKmsEncryptedObjects":{
               "Status":"Enabled"
            }
         }
      }
   ]
}

Edit the JSON to provide values for the DOC-EXAMPLE-DESTINATION-BUCKET bucket, AWS KMS key IDs (in ARN format), and IAM-role-ARN. Save the changes.
Use the following command to add the replication configuration to your DOC-EXAMPLE-SOURCE-BUCKET bucket. Be sure to provide the DOC-EXAMPLE-SOURCE-BUCKET bucket name.
```
$ aws s3api put-bucket-replication \
--replication-configuration file://replication.json \
--bucket DOC-EXAMPLE-SOURCE-BUCKET \
--profile acctA
```

Test the configuration to verify that encrypted objects are replicated. In the Amazon S3 console, do the following:
1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.
2. In the DOC-EXAMPLE-SOURCE-BUCKET bucket, create a folder named Tax.
3. Add sample objects to the folder. Be sure to choose the encryption option and specify your KMS key to encrypt the objects.
4. Verify that the DOC-EXAMPLE-DESTINATION-BUCKET bucket contains the object replicas and that they are encrypted by using the KMS key that you specified in the configuration. For more information, see Getting replication status information.

For a code example that shows how to add a replication configuration, see Using the AWS SDKs. You must modify the replication configuration appropriately.

For conceptual information, see Replicating objects created with server-side encryption (SSE-C, SSE-S3, SSE-KMS, DSSE-KMS).

Warning Javascript is disabled or is unavailable in your browser.

To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.

Document Conventions

Changing replica owner

Using S3 Replication Time Control