我正在实现一个 DRM 服务器，到目前为止 HLS 运行良好，但我在播放就绪密钥加密方面遇到了问题，我知道我需要使用来自客户端请求的公钥和许可证 Nonce（IV），但我不能找到加密算法。
来自Microsoft playReady 测试服务器的示例
客户要求：
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<AcquireLicense xmlns="http://schemas.microsoft.com/DRM/2007/03/protocols">
<challenge>
<Challenge xmlns="http://schemas.microsoft.com/DRM/2007/03/protocols/messages">
<LA xmlns="http://schemas.microsoft.com/DRM/2007/03/protocols" Id="SignedData" xml:space="preserve">
<Version>1</Version>
<ContentHeader>
<WRMHEADER xmlns="http://schemas.microsoft.com/DRM/2007/03/PlayReadyHeader" version="4.0.0.0">
<DATA>
<PROTECTINFO>
<KEYLEN>16</KEYLEN>
<ALGID>AESCTR</ALGID>
</PROTECTINFO>
<KID>7987aj+eE0uBlXi0N73AQw==</KID>
<CHECKSUM>s1zZSs3Wwow=</CHECKSUM>
<CUSTOMATTRIBUTES>
<IIS_DRM_VERSION>7.1.1064.0</IIS_DRM_VERSION>
</CUSTOMATTRIBUTES>
<LA_URL>http://playready.directtaps.net/pr/svc/rightsmanager.asmx</LA_URL>
<DS_ID>AH+03juKbUGbHl1V/QIwRA==</DS_ID>
</DATA>
</WRMHEADER>
</ContentHeader>
<CLIENTINFO>
<CLIENTVERSION>2.0.0.1446</CLIENTVERSION>
</CLIENTINFO>
<RevocationLists>
<RevListInfo>
<ListID>ioydTlK2p0WXkWklprR5Hw==</ListID>
<Version>11</Version>
</RevListInfo>
<RevListInfo>
<ListID>gC4IKKPHsUCCVhnlttibJw==</ListID>
<Version>11</Version>
</RevListInfo>
<RevListInfo>
<ListID>BOZ1zT1UnEqfCf5tJOi/kA==</ListID>
<Version>12</Version>
</RevListInfo>
<RevListInfo>
<ListID>Ef/RUojT3U6Ct2jqTCChbA==</ListID>
<Version>34</Version>
</RevListInfo>
</RevocationLists>
<LicenseNonce>e7NgfwBi1xX/egdgV9BrWQ==</LicenseNonce>
<EncryptedData xmlns="http://www.w3.org/2001/04/xmlenc#" Type="http://www.w3.org/2001/04/xmlenc#Element">
<EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes128-cbc" />
<KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<EncryptedKey xmlns="http://www.w3.org/2001/04/xmlenc#">
<EncryptionMethod Algorithm="http://schemas.microsoft.com/DRM/2007/03/protocols#ecc256" />
<KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<KeyName>WMRMServer</KeyName>
</KeyInfo>
<CipherData>
<CipherValue>W13Rs+iFyn5Qgh8iAduenxsRw3w2mOTNhfOPI6Fwv5kIn93cCauDFJexka6jtQHJ+by8wyTv4u7RofeZW9G8NakvV0JpGg7d5rEg1q1XMwy267Hecnch75FKEPSiydx2NU83IambHenRhJJ5gg3/u1aVpaXsCVtnQsv5pt5L+JM=</CipherValue>
</CipherData>
</EncryptedKey>
</KeyInfo>
<CipherData>
<CipherValue>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</CipherValue>
</CipherData>
</EncryptedData>
</LA>
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
<SignedInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
<SignatureMethod Algorithm="http://schemas.microsoft.com/DRM/2007/03/protocols#ecdsa-sha256" />
<Reference URI="#SignedData">
<DigestMethod Algorithm="http://schemas.microsoft.com/DRM/2007/03/protocols#sha256" />
<DigestValue>Y6z9FSz2qWpvIN823wrK13in0TnWGoAcPCKw9KlWZPk=</DigestValue>
</Reference>
</SignedInfo>
<SignatureValue>u45hKzad6Wir2SLSY7WTkTxpziPY2w5WTiLbNSb0RyciFV8Xm2aFyLbOCpMW33ZYubN59lsaZy8fAjUsr7ManA==</SignatureValue>
<KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<KeyValue>
<ECCKeyValue>
<PublicKey>2sumijs/TOhMhxwvkmjp4nXwJku8UXFHU+oY4fg+sRTp/pM7O3/w4k4QXAAn69pHahdLN+6OGpnQfwTv4xzGCQ==</PublicKey>
</ECCKeyValue>
</KeyValue>
</KeyInfo>
</Signature>
</Challenge>
</challenge>
</AcquireLicense>
</soap:Body>
</soap:Envelope>服务器响应：
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<AcquireLicenseResponse xmlns="http://schemas.microsoft.com/DRM/2007/03/protocols">
<AcquireLicenseResult>
<Response xmlns="http://schemas.microsoft.com/DRM/2007/03/protocols/messages">
<LicenseResponse xmlns="http://schemas.microsoft.com/DRM/2007/03/protocols">
<Version>1</Version>
<Licenses>
<License>WE1SAAAAAAN7s2B/AGLXFf96B2BX0GtZAAMAAQAAAVAAAgAEAAAACAADAAIAAAAyAAAADQAAAAoAAQABADIAAAAMAAAAIgABADQAAAAKAJYAAAAzAAAACgABAAMACQAAAPIAAQAKAAAAnu/fO2o/nhNLgZV4tDe9wEMAAQADAIDB6u6Ltq5a8s2SvNkd4kAVzxDnlUysqzX6k5epsJ4iNaZaFyLTtpgVjTRQP2lgDeJaJSIObuf2yd2Qd1tWIQDk4gXxCbUPL8NJgdvl6d4z2xBIvJq4Ol3KDiHgkYn6mYEyniIm+2IWZUrUWsKo6Z2brnsoe3GoYoNmXkJ5+kyMOgAAACoAAABMAAEAQDrjNbZngMLUdzVuWakTkwXziavX6rZhzIaQJYQOWLtJSqiFpiWTutb777SRP48Zvx2FMpyqhGdjn53dLmsiRDYAAQALAAAAHAABABB8/phYFmuGw7Y3HoQs0swN</License>
</Licenses>
<Acknowledgement>
<TransactionID>5c062475-4b2c-48e6-9b0b-54fce5b2b770</TransactionID>
</Acknowledgement>
</LicenseResponse>
</Response>
</AcquireLicenseResult>
</AcquireLicenseResponse>
</soap:Body>
</soap:Envelope>如何根据客户请求和我的 16 字节密钥创建许可证？