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# SPEKE API v2 - 覆盖密钥标识符
<a name="kid-override-v2"></a>

每轮换一次密钥，加密程序就会创建一个新的密钥标识符 (KID)。它将 KID 传递到其请求中的 DRM 密钥提供程序。通常，使用相同 KID 的密钥提供程序会响应，但它可以在响应中提供其他 KID 值。

以下是 KID 为 `11111111-1111-1111-1111-111111111111` 的示例请求：

```
<cpix:CPIX contentId="abc123" version="2.3" xmlns:cpix="urn:dashif:org:cpix" xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc">
	<cpix:ContentKeyList>
		<cpix:ContentKey explicitIV="OFj2IjCsPJFfMAxmQxLGPw==" kid="11111111-1111-1111-1111-111111111111" commonEncryptionScheme="cbcs"></cpix:ContentKey>
	</cpix:ContentKeyList>
	<cpix:DRMSystemList>
		<!-- Widevine -->
		<cpix:DRMSystem kid="11111111-1111-1111-1111-111111111111" systemId="edef8ba9-79d6-4ace-a3c8-27dcd51d21ed">
			<cpix:HLSSignalingData playlist="media"></cpix:HLSSignalingData>
			<cpix:HLSSignalingData playlist="master"></cpix:HLSSignalingData>
			<cpix:ContentProtectionData></cpix:ContentProtectionData>
			<cpix:PSSH></cpix:PSSH>
		</cpix:DRMSystem>
	</cpix:DRMSystemList>
	<cpix:ContentKeyPeriodList>
		<cpix:ContentKeyPeriod id="keyPeriod_0909829f-40ff-4625-90fa-75da3e53278f" index="1" />
	</cpix:ContentKeyPeriodList>
	<cpix:ContentKeyUsageRuleList>
		<cpix:ContentKeyUsageRule kid="11111111-1111-1111-1111-111111111111" intendedTrackType="VIDEO">
			<cpix:KeyPeriodFilter periodId="keyPeriod_0909829f-40ff-4625-90fa-75da3e53278f"/>
			<cpix:VideoFilter />
		</cpix:ContentKeyUsageRule>
	</cpix:ContentKeyUsageRuleList>
</cpix:CPIX>
```

以下响应将 KID 覆盖为 `22222222-2222-2222-2222-222222222222`：

```
<cpix:CPIX contentId="abc123" version="2.3" xmlns:cpix="urn:dashif:org:cpix" xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc">
	<cpix:ContentKeyList>
		<cpix:ContentKey explicitIV="OFj2IjCsPJFfMAxmQxLGPw==" kid="22222222-2222-2222-2222-222222222222" commonEncryptionScheme="cbcs">
			<cpix:Data>
				<pskc:Secret>
					<pskc:PlainValue>5dGAgwGuUYu4dHeHtNlxJw==</pskc:PlainValue>
				</pskc:Secret>
			</cpix:Data>
		</cpix:ContentKey>
	</cpix:ContentKeyList>
	<cpix:DRMSystemList>
		<!-- Widevine -->
		<cpix:DRMSystem kid="22222222-2222-2222-2222-222222222222" systemId="edef8ba9-79d6-4ace-a3c8-27dcd51d21ed">
			<cpix:HLSSignalingData playlist="media">Ifa2V5LWl[...]nNB</cpix:HLSSignalingData>
			<cpix:HLSSignalingData playlist="master">oIARIQeSI[...]Nd2l</cpix:HLSSignalingData>
			<cpix:ContentProtectionData>RoNd2lkZXZ[...]Nib</cpix:ContentProtectionData>
			<cpix:PSSH>AAAAanBzc[...]A==</cpix:PSSH>
		</cpix:DRMSystem>
	</cpix:DRMSystemList>
	<cpix:ContentKeyPeriodList>
		<cpix:ContentKeyPeriod id="keyPeriod_0909829f-40ff-4625-90fa-75da3e53278f" index="1" />
	</cpix:ContentKeyPeriodList>
	<cpix:ContentKeyUsageRuleList>
		<cpix:ContentKeyUsageRule kid="22222222-2222-2222-2222-222222222222" intendedTrackType="VIDEO">
			<cpix:KeyPeriodFilter periodId="keyPeriod_0909829f-40ff-4625-90fa-75da3e53278f"/>
			<cpix:VideoFilter />
		</cpix:ContentKeyUsageRule>
	</cpix:ContentKeyUsageRuleList>
</cpix:CPIX>
```