Functions

With SSE-KMS, OBS uses the keys provided by Key Management Service (KMS) for server-side encryption. You can create custom keys on KMS to encrypt your objects. If you do not specify a key, OBS creates a default key the first time you upload an object to the bucket. Custom keys or default keys are used to encrypt and decrypt data encryption keys (DEKs).

When a custom key in a non-default IAM project is used to encrypt objects, only the key owner can upload or download the encrypted objects.

Newly Added Headers

Two headers are added for SSE-KMS. You can configure the headers listed in Table 1 to enable SSE-KMS.

You can also configure the default encryption for a bucket to encrypt objects you upload to the bucket. After default encryption is enabled for a bucket, any object upload request without encryption header included will inherit the bucket's encryption settings. For details, see Configuring Bucket Encryption.

**Table 1** Header fields used in SSE-KMS mode
Element	Description
x-obs-server-side-encryption	Indicates that SSE-KMS is used for encrypting objects. Type: string Example: x-obs-server-side-encryption:kms
x-obs-server-side-encryption-kms-key-id	Indicates the master key for encrypting the object when SSE-KMS is used. If this header is not provided, the default master key will be used. If there is no such a default master key, OBS will create one and use it by default. Type: string The following two formats are supported: - regionID:domainID:key/key_id - key_id regionID indicates the ID of the region where the key belongs. domainID indicates the ID of the tenant where the key belongs. key_id indicates the ID of the key created in KMS. Examples: - x-obs-server-side-encryption-kms-key-id:region:domainiddomainiddomainiddoma0001:key/4f1cd4de-ab64-4807-920a-47fc42e7f0d0 - x-obs-server-side-encryption-kms-key-id:4f1cd4de-ab64-4807-920a-47fc42e7f0d0

APIs Where SSE-KMS Headers Apply

You can configure headers about SSE-KMS in the APIs below:

Uploading Objects - PUT
Uploading Objects - POST: x-obs-server-side-encryption and x-obs-server-side-encryption-kms-key-id need to be placed in the form instead of headers.
Copying Objects (The newly added headers apply to object copies.)
Initiating a Multipart Upload

You can configure a bucket policy to restrict the request headers for a specified bucket. For example, if you require that object upload requests do not contain header x-obs-server-side-encryption:"kms", you can use the following bucket policy:

{
    "Statement": [
        {
            "Sid": "DenyUnEncryptedObjectUploads",
            "Effect": "Deny",
            "Principal": "*",
            "Action": "PutObject",
            "Resource": "YourBucket/*",
            "Condition": {
                "StringNotEquals": {
                    "x-obs-server-side-encryption": "kms"
                }
            }
        }
    ]
}

Sample Request: Using the Default Key to Encrypt an Object

PUT /encryp1 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: Wed, 06 Jun 2018 09:08:21 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:f3/7eS6MFbW3JO4+7I5AtyAQENU=
x-obs-server-side-encryption:kms
Content-Length: 5242
Expect: 100-continue

[5242 Byte object contents]

Sample Response: Using the Default Key to Encrypt an Object

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 8DF400000163D45AA81D038B6AE4C482
ETag: "d8bffdfbab5345d91ac05141789d2477"
x-obs-server-side-encryption: kms
x-obs-server-side-encryption-kms-key-id: region:783fc6652cf246c096ea836694f71855:key/522d6070-5ad3-4765-9737-9312ddc72cdb
x-obs-id-2: 32AAAUJAIAABAAAQAAEAABAAAQAAEAABCTv7cHmAnGfBAGXUHeibUsiETTNqlCqC
Date: Wed, 06 Jun 2018 09:08:21 GMT
Content-Length: 0

Sample Request: Using a Custom Key to Encrypt an Object

PUT /encryp1 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: Wed, 06 Jun 2018 09:08:50 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:f3/PWjkXYTYGs5lPOctTNEI2QENU=
x-obs-server-side-encryption:kms
x-obs-server-side-encryption-kms-key-id: 522d6070-5ad3-4765-43a7-a7d1-ab21f498482d
Content-Length: 5242
Expect: 100-continue

[5242 Byte object contents]

Sample Response: Using a Custom Key to Encrypt an Object

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 8DF400000163D45AA81D038B6AE4C482
ETag: "d8bffdfbab5345d91ac05141789d2477"
x-obs-server-side-encryption: kms
x-obs-server-side-encryption-kms-key-id: region:783fc6652cf246c096ea836694f71855:key/522d6070-5ad3-4765-43a7-a7d1-ab21f498482d
x-obs-id-2: 32AAAUJAIAABAdiAEAABA09AEAABCTv7cHmAn12BAG83ibUsiET5eqlCqg
Date: Wed, 06 Jun 2018 09:08:50 GMT
Content-Length: 0

Sample Request: Using a Key to Encrypt an Object Copy

PUT /destobject HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
x-obs-server-side-encryption:kms
x-obs-server-side-encryption-kms-key-id: region:783fc6652cf246c096ea836694f71855:key/522d6070-5ad3-4765-9737-9312ddc72cdb
Accept: */*
Date: Wed, 06 Jun 2018 09:10:29 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:SH3uTrElaGWarVI1uTq325kTVCI=
x-obs-copy-source: /bucket/srcobject1

Sample Response: Using a Key to Encrypt an Object Copy

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: BB78000001648480AF3900CED7F15155
ETag: "d8bffdfbab5345d91ac05141789d2477"
x-obs-server-side-encryption: kms
x-obs-server-side-encryption-kms-key-id: region:783fc6652cf246c096ea836694f71855:key/522d6070-5ad3-4765-9737-9312ddc72cdb
x-obs-id-2: oRAXhgwdaLc9wKVHqTLSmQB7I35D+32AAAUJAIAABAAAQAAEAABAAAQAAEAABCS
Date: Wed, 06 Jun 2018 09:10:29 GMT
Content-Length: 0

Sample Request: Uploading an Encrypted Object Using a Signed URL

PUT /destobject?AccessKeyId=UI3SN1SRUQE14OYBKTZB&Expires=1534152518&x-obs-server-side-encryption=kms&Signature=chvmG7%2FDA%2FDCQmTRJu3xngldJpg%3D HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: Wed, 06 Jun 2018 09:10:29 GMT

Sample Response: Uploading an Encrypted Object Using a Signed URL

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: BB78000001648480AF3900CED7F15155
ETag: "d8bffdfbab5345d91ac05141789d2477"
x-obs-server-side-encryption: kms
x-obs-server-side-encryption-kms-key-id: region:783fc6652cf246c096ea836694f71855:key/522d6070-5ad3-4765-9737-9312ddc72cdb
x-obs-id-2: oRAXhgwdaLc9wKVHqTLSmQB7I35D+32AAAUJAIAABAAAQAAEAABAAAQAAEAABCS
Date: Wed, 06 Jun 2018 09:10:29 GMT
Content-Length: 0