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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <utils/Errors.h>
     18 
     19 #ifndef CRYPTO_API_H_
     20 
     21 #define CRYPTO_API_H_
     22 
     23 namespace android {
     24 
     25 struct AString;
     26 struct CryptoPlugin;
     27 
     28 struct CryptoFactory {
     29     CryptoFactory() {}
     30     virtual ~CryptoFactory() {}
     31 
     32     virtual bool isCryptoSchemeSupported(const uint8_t uuid[16]) const = 0;
     33 
     34     virtual status_t createPlugin(
     35             const uint8_t uuid[16], const void *data, size_t size,
     36             CryptoPlugin **plugin) = 0;
     37 
     38 private:
     39     CryptoFactory(const CryptoFactory &);
     40     CryptoFactory &operator=(const CryptoFactory &);
     41 };
     42 
     43 struct CryptoPlugin {
     44     enum Mode {
     45         kMode_Unencrypted = 0,
     46         kMode_AES_CTR     = 1,
     47 
     48         // Neither key nor iv are being used in this mode.
     49         // Each subsample is encrypted w/ an iv of all zeroes.
     50         kMode_AES_WV      = 2,  // FIX constant
     51     };
     52 
     53     struct SubSample {
     54         uint32_t mNumBytesOfClearData;
     55         uint32_t mNumBytesOfEncryptedData;
     56     };
     57 
     58     CryptoPlugin() {}
     59     virtual ~CryptoPlugin() {}
     60 
     61     // If this method returns false, a non-secure decoder will be used to
     62     // decode the data after decryption. The decrypt API below will have
     63     // to support insecure decryption of the data (secure = false) for
     64     // media data of the given mime type.
     65     virtual bool requiresSecureDecoderComponent(const char *mime) const = 0;
     66 
     67     // To implement resolution constraints, the crypto plugin needs to know
     68     // the resolution of the video being decrypted.  The media player should
     69     // call this method when the resolution is determined and any time it
     70     // is subsequently changed.
     71     virtual void notifyResolution(uint32_t width, uint32_t height) {}
     72 
     73     // If the error returned falls into the range
     74     // ERROR_DRM_VENDOR_MIN..ERROR_DRM_VENDOR_MAX, errorDetailMsg should be
     75     // filled in with an appropriate string.
     76     // At the java level these special errors will then trigger a
     77     // MediaCodec.CryptoException that gives clients access to both
     78     // the error code and the errorDetailMsg.
     79     // Returns a non-negative result to indicate the number of bytes written
     80     // to the dstPtr, or a negative result to indicate an error.
     81     virtual ssize_t decrypt(
     82             bool secure,
     83             const uint8_t key[16],
     84             const uint8_t iv[16],
     85             Mode mode,
     86             const void *srcPtr,
     87             const SubSample *subSamples, size_t numSubSamples,
     88             void *dstPtr,
     89             AString *errorDetailMsg) = 0;
     90 
     91 private:
     92     CryptoPlugin(const CryptoPlugin &);
     93     CryptoPlugin &operator=(const CryptoPlugin &);
     94 };
     95 
     96 }  // namespace android
     97 
     98 extern "C" {
     99     extern android::CryptoFactory *createCryptoFactory();
    100 }
    101 
    102 #endif  // CRYPTO_API_H_
    103