feat(tutorial): add tutorial to store sse-c key into secret manager

tutorials/object-storage-sse-c-with-secret-manager/index.mdx

@@ -0,0 +1,125 @@
+---
+meta:
+  title: Using Secret Manager to store encryption key for SSE-C
+  description: Learn how to use Secret Manager to store encryption key for Object Storage and SSE-C.
+tags: object-storage secret-manager encryption
+products:
+  - object-storage
+  - secret-manager
+  - key-manager
+dates:
+  validation: 2025-10-28
+  posted: 2025-10-28
+  validation_frequency: 12
+difficulty: beginner
+usecase:
+  - manage-share-and-store-data
+ecosystem:
+  - scaleway-only
+---
+import Requirements from '@macros/iam/requirements.mdx'
+
+This tutorial explains how to use Key Manager and Secret Manager to generate and store an encryption key for [SSE-C](/object-storage/api-cli/enable-sse-c/), used to encrypt and decrypt objects in your Scaleway Object Storage bucket.
+
+<Requirements />
+
+- A Scaleway account logged into the [console](https://console.scaleway.com)
+- [Owner](/iam/concepts/#owner) status or [IAM permissions](/iam/concepts/#permission) allowing you to perform actions in the intended Organization
+- [Created](/object-storage/how-to/create-a-bucket/) an Object Storage bucket
+- Installed and initialized the [AWS CLI](/object-storage/api-cli/object-storage-aws-cli/)
+
+The goal of this tutorial is to:
+
+- Generate an encryption key using Key Manager
+- Store it securely in Secret Manager
+- Use it to encrypt your Object Storage objects with SSE-C
+
+## Generating the encryption key
+
+1. Open a terminal and create a key in Key Manager:
+
+    ```bash
+    KEY_ID=$(scw keymanager key create -o template="{{.ID}}")
+    ```
+
+2. Run the following command to generate a data encryption key:
+
+    ```bash
+    scw keymanager key generate-data-key "$KEY_ID" -o json | jq -r .plaintext | base64 -d > ssec.key
+    ```
+
+3. Create a secret in Secret manager to store the data encryption key:
+
+    ```bash
+    SECRET_ID=$(scw secret secret create name=ssec-key path=/keys -o template="{{.ID}}")
+    ```
+
+4. Store the data encryption key in Secret Manager:
+
+    ```bash
+    scw secret version create "$SECRET_ID" data="@ssec.key"
+    ```
+
+## Preparing the encryption key and its digest
+
+You must now retrieve the encryption key from Secret Manager, encode it to base64, compute its MD5 digest, and store both values in environment variables.
+
+1. Access the secret version to retrieve the raw key:
+
+      ```bash
+      scw secret version access "$SECRET_ID" revision=latest raw=true > ssec.key
+      ```
+
+2. Encode the key to base64:
+
+    ```bash
+    ENCRYPTION_KEY=$(cat ssec.key | base64)
+    ```
+
+3. Compute the MD5 digest of the key:
+
+    ```bash
+    KEY_DIGEST=$(openssl dgst -md5 -binary ssec.key | base64)
+    ```
+
+<Message type="important">
+ If you delete the secret containing the encryption key, you also lose the data encrypted with it, as you will not be able to perform `GET` operations on encrypted objects without the corresponding key.
+</Message>
+
+### Upload and download objects with SSE-C
+
+1. Upload an object of your choice to your bucket and encrypt it. Make sure that you replace:
+
+    - `<bucket-name>` with the name of your bucket
+    - `<object-key>` with the desired name of the object in the bucket
+    - `<path/to/your/file>` with the path to the file you want to upload
+
+    ```bash
+    aws s3api put-object \
+      --bucket <bucket-name> \
+      --key <object-key> \
+      --body <path/to/your/file> \
+      --sse-customer-algorithm AES256 \
+      --sse-customer-key $ENCRYPTION_KEY \
+      --sse-customer-key-md5 $KEY_DIGEST
+    ```
+
+2. Download the previously uploaded object and decrypt it. Make sure that you replace:
+
+    - `<bucket-name>` with the name of your bucket
+    - `<object-key>` with the name of your object in the bucket
+    - `<path/to/your/file>` with the local path where you want to save the file
+
+    ```bash
+    aws s3api get-object \
+      --bucket <bucket-name> \
+      --key <object-key> \
+      <path/to/destination/file> \
+      --sse-customer-algorithm AES256 \
+      --sse-customer-key $ENCRYPTION_KEY \
+      --sse-customer-key-md5 $KEY_DIGEST
+    ```
+
+You now know how to use Key Manager and Secret Manager to generate, store, and use an encryption key to protect your Object Storage data with SSE-C.
+
+Refer to the [dedicated documentation](/object-storage/api-cli/enable-sse-c/) for more information on how to use SSE-C for Scaleway Object Storage.