Snippet Name: Create_certificate_from_VARBINARY

Tags:

Created Date: 2025-06-16 13:12:42
Last Modified Date: 2025-05-31 10:32:00

Dependencies:

DBA Notes:

Sample Output:

Title: Create certificate from VARBINARY
Author: user
in sql server, i want to create a certificate and import it to another suite of servers.  instead of disk based restore, like the command below, can i create a certificate from varbinary strings? 

Author: ChatGPT
Yes, in SQL Server, you can create a certificate directly from a `VARBINARY` value using the `FROM BINARY =` option. This allows you to store the certificate information in a table or pass it in a script instead of restoring it from disk.

Here???s an example of how you can create and then export a certificate in one server, and later import it into another server using `VARBINARY` values.

---

### Step 1: Create and Export Certificate

1. **Create the Certificate:**
   ```sql
   CREATE CERTIFICATE MyCertificate
   WITH SUBJECT = 'My Test Certificate';
   ```

2. **Backup the Certificate to VARBINARY:**
   Extract the certificate and private key to `VARBINARY` values:
   ```sql
   DECLARE @Cert NVARCHAR(128) = 'MyCertificate';
   DECLARE @PublicKey VARBINARY(MAX), @PrivateKey VARBINARY(MAX);

   -- Export the public key
   SELECT @PublicKey = CERTENCODED(@Cert);

   -- Export the private key
   SELECT @PrivateKey = CERTPRIVATEKEY(@Cert, 'StrongPasswordHere');

   -- Store them in a table or output for transfer
   SELECT @PublicKey AS PublicKey, @PrivateKey AS PrivateKey;
   ```

   Replace `'StrongPasswordHere'` with the actual password to secure the private key.

---

### Step 2: Import Certificate on Another Server

1. **Prepare the `VARBINARY` Values:**
   Transfer the `VARBINARY` values to the target server via a secure method, such as a table or script.

2. **Recreate the Certificate from `VARBINARY`:**
   ```sql
   DECLARE @PublicKey VARBINARY(MAX) = -- Paste the public key VARBINARY value here
   DECLARE @PrivateKey VARBINARY(MAX) = -- Paste the private key VARBINARY value here
   DECLARE @Password NVARCHAR(MAX) = 'StrongPasswordHere'; -- Same password used for export

   CREATE CERTIFICATE MyCertificate
   FROM BINARY = @PublicKey
   WITH PRIVATE KEY (BINARY = @PrivateKey, DECRYPTION BY PASSWORD = @Password);
   ```

---

### Notes
1. **Encryption Password:** Ensure you use a strong and secure password for the private key during export and import.
2. **Permissions:** The user running these commands must have appropriate permissions to manage certificates (`CONTROL` permission on the database or `sysadmin` role).
3. **Environment Consistency:** The target environment must support certificates (e.g., SQL Server Standard or Enterprise edition).

Using `VARBINARY` for certificate management eliminates the need for disk-based operations and allows you to transfer certificates securely within scripts or as part of database metadata.

Author: user
ok, i have the two files DatabaseBackupEncryption_20240321.cert and DatabaseBackupEncryption_20240321.key on disk in C:\temp that i need to convert to binary for this operation; how can i do that?

Author: ChatGPT
To convert the `.cert` and `.key` files on disk into `VARBINARY` format for SQL Server, you can use the `OPENROWSET` or `BULK` function to read the file contents as binary data. Here's how you can do it:

---

### Step 1: Enable Ad Hoc Distributed Queries (if needed)

Ensure that the `Ad Hoc Distributed Queries` option is enabled, as it's required for the `OPENROWSET` function.

```sql
EXEC sp_configure 'show advanced options', 1;
RECONFIGURE;
EXEC sp_configure 'Ad Hoc Distributed Queries', 1;
RECONFIGURE;
```

---

### Step 2: Load the Certificate and Key Files into `VARBINARY`

1. **Read the `.cert` file:**

   ```sql
   DECLARE @CertBinary VARBINARY(MAX);

   SELECT @CertBinary = BulkColumn
   FROM OPENROWSET(BULK 'C:\temp\DatabaseBackupEncryption_20240321.cert', SINGLE_BLOB) AS CertificateFile;

   PRINT @CertBinary; -- Optional: Verify the binary data
   ```

2. **Read the `.key` file:**

   ```sql
   DECLARE @KeyBinary VARBINARY(MAX);

   SELECT @KeyBinary = BulkColumn
   FROM OPENROWSET(BULK 'C:\temp\DatabaseBackupEncryption_20240321.key', SINGLE_BLOB) AS KeyFile;

   PRINT @KeyBinary; -- Optional: Verify the binary data
   ```

---

### Step 3: Use the `VARBINARY` Values to Recreate the Certificate

Once you have loaded the binary data, you can use it to recreate the certificate in SQL Server:

```sql
CREATE CERTIFICATE DatabaseBackupEncryption
FROM BINARY = @CertBinary
WITH PRIVATE KEY (BINARY = @KeyBinary, DECRYPTION BY PASSWORD = 'YourSecurePassword');
```

---

### Additional Notes

1. **File Path Access:** Ensure the SQL Server service account has permission to read files in the `C:\temp` directory.
2. **Binary Size:** Both the `.cert` and `.key` files should be manageable in size. If they are unusually large, ensure sufficient memory is available.
3. **Secure Password:** Use the correct password for the private key. This password is the one you used when exporting the key initially.
4. **Cleanup:** After successful execution, consider removing sensitive files (`.cert` and `.key`) from disk to maintain security.

This approach ensures you can handle the files securely and recreate the certificate without relying on disk-based restores.