Features of Secure Audio Path
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Features of Secure Audio Path
You can enable the features of Secure Audio Path (SAP), as described in the following table.
| SAP level | SAP required |
Drivers verified |
Digital output disabled |
| Secure Audio Path is not required. Content works on Microsoft Windows 98, Windows NT version 4 (with Service Pack 6), Windows 2000, and Windows Millennium Edition. | No | No | No |
| This level is the weakest, but permits a larger number of consumers initially. This mode enables you to secure your files beyond the player , and is the best chance that consumers will have the necessary software components to play files. Supported on Windows Millennium Edition and Windows XP. | Yes | No | No |
| This level ensures that consumers are using SAP-certified drivers. Supported on Windows Millennium Edition and Windows XP. | Yes | Yes | No |
| This level currently offers the highest level of security. Supported on Windows Millennium Edition and Windows XP. | Yes | Yes | Yes |
To accommodate different DRM scenarios, you can enable different business models. When you receive a license request, determine whether it is from a computer that supports Secure Audio Path. Use the WMRMChallenge.CheckClientCapability property by using SAPMode as a parameter value, as shown in the following example:
bSupportSAP = Challenge.CheckClientCapability("SAPMode")
if (bSupportSAP = true) then
' The client supports Secure Audio Path.
Endif
If you want extremely secure digital media files, you might issue licenses only to computers that support Secure Audio Path, and then in the license require Secure Audio Path mode 1 or higher. Another option is to charge different rates depending on the consumer's operating system; for example, you can charge less for licenses that are issued to computers that support Secure Audio Path. You have great flexibility in determining the business model you want to use.
Note Computers that support Secure Audio Path can also play Windows Media files that do not require Secure Audio Path; this feature is implemented only when required by a license.
In addition to enabling different SAP features, you can specify the minimum security level that drivers must have. Each signed audio driver has a security level, and content owners can specify the minimum security level a driver must have to play their packaged files.
The operating system determines the security level of the drivers, as described in the following table.
| Platform | SAP-compliant driver security level |
| Windows Millennium Edition | 1100 |
| Windows XP | 1200 |
Note Windows Vista does not support SAP. If you require SAP for your content, users of Windows Vista can play it only with an application that is based on the Microsoft Media Foundation SDK, which then uses the Protected User Mode Audio (PUMA) feature.
See Also
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