109 lines
3.9 KiB
C++
109 lines
3.9 KiB
C++
// Copyright 2016 Google Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#ifndef PACKAGER_MEDIA_BASE_AES_CRYPTOR_H_
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#define PACKAGER_MEDIA_BASE_AES_CRYPTOR_H_
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#include <string>
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#include <vector>
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#include "packager/base/macros.h"
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#include "packager/base/memory/scoped_ptr.h"
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#include "packager/media/base/fourccs.h"
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struct aes_key_st;
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typedef struct aes_key_st AES_KEY;
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namespace edash_packager {
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namespace media {
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// AES cryptor interface. Inherited by various AES encryptor and decryptor
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// implementations.
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class AesCryptor {
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public:
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AesCryptor();
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virtual ~AesCryptor();
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/// Initialize the cryptor with specified key and IV.
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/// @return true on successful initialization, false otherwise.
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virtual bool InitializeWithIv(const std::vector<uint8_t>& key,
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const std::vector<uint8_t>& iv) = 0;
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/// @name Various forms of crypt (Encrypt/Decrypt) calls.
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/// It is an Encrypt function for encryptor and a Decrypt function for
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/// decryptor. The text and crypt_text pointers can be the same address for
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/// in place encryption/decryption.
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/// @{
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bool Crypt(const std::vector<uint8_t>& text,
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std::vector<uint8_t>* crypt_text);
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bool Crypt(const std::string& text, std::string* crypt_text);
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/// @param crypt_text should have at least @a text_size bytes.
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bool Crypt(const uint8_t* text, size_t text_size, uint8_t* crypt_text) {
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size_t crypt_text_size = text_size;
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return CryptInternal(text, text_size, crypt_text, &crypt_text_size);
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}
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/// @}
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/// Set IV.
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/// @return true if successful, false if the input is invalid.
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virtual bool SetIv(const std::vector<uint8_t>& iv) = 0;
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/// Update IV for next sample. As recommended in ISO/IEC 23001-7: IV need to
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/// be updated per sample for CENC.
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/// This is used by encryptors only.
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virtual void UpdateIv() = 0;
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/// @return The current iv.
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const std::vector<uint8_t>& iv() const { return iv_; }
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/// @param protection_scheme specifies the protection scheme: 'cenc', 'cens',
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/// 'cbc1', 'cbcs', which is useful to determine the random iv size.
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/// @param iv points to generated initialization vector.
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/// @return true on success, false otherwise.
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static bool GenerateRandomIv(FourCC protection_scheme,
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std::vector<uint8_t>* iv);
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protected:
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void set_iv(const std::vector<uint8_t>& iv) { iv_ = iv; }
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const AES_KEY* aes_key() const { return aes_key_.get(); }
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AES_KEY* mutable_aes_key() { return aes_key_.get(); }
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private:
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// Internal implementation of crypt function.
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// |text| points to the input text.
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// |text_size| is the size of input text.
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// |crypt_text| points to the output encrypted or decrypted text, depends on
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// whether it is an encryption or decryption. |text| and |crypt_text| can
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// point to the same address for in place encryption/decryption.
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// |crypt_text_size| contains the size of |crypt_text| and it will be updated
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// to contain the actual encrypted/decrypted size for |crypt_text| on success.
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// Return false if the input |crypt_text_size| is not large enough to hold the
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// output |crypt_text| or if there is any error in encryption/decryption.
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virtual bool CryptInternal(const uint8_t* text,
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size_t text_size,
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uint8_t* crypt_text,
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size_t* crypt_text_size) = 0;
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// |size| specifies the input text size.
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// Return the number of padding bytes needed.
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// Note: No paddings should be needed except for pkcs5-cbc encryptor.
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virtual size_t NumPaddingBytes(size_t size) const;
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// Initialization vector, with size 8 or 16.
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std::vector<uint8_t> iv_;
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// Openssl AES_KEY.
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scoped_ptr<AES_KEY> aes_key_;
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DISALLOW_COPY_AND_ASSIGN(AesCryptor);
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};
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} // namespace media
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} // namespace edash_packager
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#endif // PACKAGER_MEDIA_BASE_AES_CRYPTOR_H_
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