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< li class = "navelem" > < a class = "el" href = "../../dir_39dc0668bd5a501998f94e8b4e546c71.html" > media< / a > < / li > < li class = "navelem" > < a class = "el" href = "../../dir_c6ada2450b25ab5438a4dba6c9b890af.html" > base< / a > < / li > < / ul >
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< div class = "title" > aes_decryptor.cc< / div > < / div >
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< div class = "contents" >
< div class = "fragment" > < div class = "line" > < a name = "l00001" > < / a > < span class = "lineno" > 1< / span >   < span class = "comment" > // Copyright 2016 Google Inc. All rights reserved.< / span > < / div >
< div class = "line" > < a name = "l00002" > < / a > < span class = "lineno" > 2< / span >   < span class = "comment" > //< / span > < / div >
< div class = "line" > < a name = "l00003" > < / a > < span class = "lineno" > 3< / span >   < span class = "comment" > // Use of this source code is governed by a BSD-style< / span > < / div >
< div class = "line" > < a name = "l00004" > < / a > < span class = "lineno" > 4< / span >   < span class = "comment" > // license that can be found in the LICENSE file or at< / span > < / div >
< div class = "line" > < a name = "l00005" > < / a > < span class = "lineno" > 5< / span >   < span class = "comment" > // https://developers.google.com/open-source/licenses/bsd< / span > < / div >
< div class = "line" > < a name = "l00006" > < / a > < span class = "lineno" > 6< / span >   < / div >
< div class = "line" > < a name = "l00007" > < / a > < span class = "lineno" > 7< / span >   < span class = "preprocessor" > #include " packager/media/base/aes_decryptor.h" < / span > < / div >
< div class = "line" > < a name = "l00008" > < / a > < span class = "lineno" > 8< / span >   < / div >
< div class = "line" > < a name = "l00009" > < / a > < span class = "lineno" > 9< / span >   < span class = "preprocessor" > #include < openssl/aes.h> < / span > < / div >
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< div class = "line" > < a name = "l00010" > < / a > < span class = "lineno" > 10< / span >   < span class = "preprocessor" > #include < algorithm> < / span > < / div >
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< div class = "line" > < a name = "l00011" > < / a > < span class = "lineno" > 11< / span >   < span class = "preprocessor" > #include " packager/base/logging.h" < / span > < / div >
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< div class = "line" > < a name = "l00012" > < / a > < span class = "lineno" > 12< / span >   < / div >
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< div class = "line" > < a name = "l00013" > < / a > < span class = "lineno" > 13< / span >   < span class = "keyword" > namespace < / span > {< / div >
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< div class = "line" > < a name = "l00014" > < / a > < span class = "lineno" > 14< / span >   < / div >
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< div class = "line" > < a name = "l00015" > < / a > < span class = "lineno" > 15< / span >   < span class = "comment" > // AES defines three key sizes: 128, 192 and 256 bits.< / span > < / div >
< div class = "line" > < a name = "l00016" > < / a > < span class = "lineno" > 16< / span >   < span class = "keywordtype" > bool< / span > IsKeySizeValidForAes(< span class = "keywordtype" > size_t< / span > key_size) {< / div >
< div class = "line" > < a name = "l00017" > < / a > < span class = "lineno" > 17< / span >   < span class = "keywordflow" > return< / span > key_size == 16 || key_size == 24 || key_size == 32;< / div >
< div class = "line" > < a name = "l00018" > < / a > < span class = "lineno" > 18< / span >   }< / div >
< div class = "line" > < a name = "l00019" > < / a > < span class = "lineno" > 19< / span >   < / div >
< div class = "line" > < a name = "l00020" > < / a > < span class = "lineno" > 20< / span >   } < span class = "comment" > // namespace< / span > < / div >
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< div class = "line" > < a name = "l00021" > < / a > < span class = "lineno" > 21< / span >   < / div >
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< div class = "line" > < a name = "l00022" > < / a > < span class = "lineno" > 22< / span >   < span class = "keyword" > namespace < / span > shaka {< / div >
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< div class = "line" > < a name = "l00023" > < / a > < span class = "lineno" > 23< / span >   < span class = "keyword" > namespace < / span > media {< / div >
< div class = "line" > < a name = "l00024" > < / a > < span class = "lineno" > 24< / span >   < / div >
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< div class = "line" > < a name = "l00025" > < / a > < span class = "lineno" > < a class = "line" href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a855ab9fa2f350879a7716ec90033f825" > 25< / a > < / span >   < a class = "code" href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a855ab9fa2f350879a7716ec90033f825" > AesCbcDecryptor::AesCbcDecryptor< / a > (CbcPaddingScheme padding_scheme)< / div >
< div class = "line" > < a name = "l00026" > < / a > < span class = "lineno" > 26< / span >   : < a class = "code" href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html" > AesCbcDecryptor< / a > (padding_scheme, kDontUseConstantIv) {}< / div >
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< div class = "line" > < a name = "l00027" > < / a > < span class = "lineno" > 27< / span >   < / div >
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< div class = "line" > < a name = "l00028" > < / a > < span class = "lineno" > < a class = "line" href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a350d11c34c42ee4d4e62cdd7aebc5fbb" > 28< / a > < / span >   < a class = "code" href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a855ab9fa2f350879a7716ec90033f825" > AesCbcDecryptor::AesCbcDecryptor< / a > (CbcPaddingScheme padding_scheme,< / div >
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< div class = "line" > < a name = "l00029" > < / a > < span class = "lineno" > 29< / span >   ConstantIvFlag constant_iv_flag)< / div >
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< div class = "line" > < a name = "l00030" > < / a > < span class = "lineno" > 30< / span >   : < a class = "code" href = "../../df/d87/classshaka_1_1media_1_1AesCryptor.html" > AesCryptor< / a > (constant_iv_flag), padding_scheme_(padding_scheme) {< / div >
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< div class = "line" > < a name = "l00031" > < / a > < span class = "lineno" > 31< / span >   < span class = "keywordflow" > if< / span > (padding_scheme_ != kNoPadding) {< / div >
< div class = "line" > < a name = "l00032" > < / a > < span class = "lineno" > 32< / span >   CHECK_EQ(constant_iv_flag, kUseConstantIv)< / div >
< div class = "line" > < a name = "l00033" > < / a > < span class = "lineno" > 33< / span >   < < < span class = "stringliteral" > " non-constant iv (cipher block chain across calls) only makes sense " < / span > < / div >
< div class = "line" > < a name = "l00034" > < / a > < span class = "lineno" > 34< / span >   < span class = "stringliteral" > " if the padding_scheme is kNoPadding." < / span > ;< / div >
< div class = "line" > < a name = "l00035" > < / a > < span class = "lineno" > 35< / span >   }< / div >
< div class = "line" > < a name = "l00036" > < / a > < span class = "lineno" > 36< / span >   }< / div >
< div class = "line" > < a name = "l00037" > < / a > < span class = "lineno" > 37< / span >   < / div >
< div class = "line" > < a name = "l00038" > < / a > < span class = "lineno" > 38< / span >   AesCbcDecryptor::~AesCbcDecryptor() {}< / div >
< div class = "line" > < a name = "l00039" > < / a > < span class = "lineno" > 39< / span >   < / div >
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< div class = "line" > < a name = "l00040" > < / a > < span class = "lineno" > < a class = "line" href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a71ff0b9654de96f9990b29c35fa9b7bf" > 40< / a > < / span >   < span class = "keywordtype" > bool< / span > < a class = "code" href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a71ff0b9654de96f9990b29c35fa9b7bf" > AesCbcDecryptor::InitializeWithIv< / a > (< span class = "keyword" > const< / span > std::vector< uint8_t> & key,< / div >
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< div class = "line" > < a name = "l00041" > < / a > < span class = "lineno" > 41< / span >   < span class = "keyword" > const< / span > std::vector< uint8_t> & iv) {< / div >
< div class = "line" > < a name = "l00042" > < / a > < span class = "lineno" > 42< / span >   < span class = "keywordflow" > if< / span > (!IsKeySizeValidForAes(key.size())) {< / div >
< div class = "line" > < a name = "l00043" > < / a > < span class = "lineno" > 43< / span >   LOG(ERROR) < < < span class = "stringliteral" > " Invalid AES key size: " < / span > < < key.size();< / div >
< div class = "line" > < a name = "l00044" > < / a > < span class = "lineno" > 44< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > false< / span > ;< / div >
< div class = "line" > < a name = "l00045" > < / a > < span class = "lineno" > 45< / span >   }< / div >
< div class = "line" > < a name = "l00046" > < / a > < span class = "lineno" > 46< / span >   < / div >
< div class = "line" > < a name = "l00047" > < / a > < span class = "lineno" > 47< / span >   CHECK_EQ(AES_set_decrypt_key(key.data(), key.size() * 8, mutable_aes_key()),< / div >
< div class = "line" > < a name = "l00048" > < / a > < span class = "lineno" > 48< / span >   0);< / div >
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< div class = "line" > < a name = "l00049" > < / a > < span class = "lineno" > 49< / span >   < span class = "keywordflow" > return< / span > < a class = "code" href = "../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a4875146da4761bb757d6b00132ae6fea" > SetIv< / a > (iv);< / div >
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< div class = "line" > < a name = "l00050" > < / a > < span class = "lineno" > 50< / span >   }< / div >
< div class = "line" > < a name = "l00051" > < / a > < span class = "lineno" > 51< / span >   < / div >
< div class = "line" > < a name = "l00052" > < / a > < span class = "lineno" > 52< / span >   < span class = "keywordtype" > bool< / span > AesCbcDecryptor::CryptInternal(< span class = "keyword" > const< / span > uint8_t* ciphertext,< / div >
< div class = "line" > < a name = "l00053" > < / a > < span class = "lineno" > 53< / span >   < span class = "keywordtype" > size_t< / span > ciphertext_size,< / div >
< div class = "line" > < a name = "l00054" > < / a > < span class = "lineno" > 54< / span >   uint8_t* plaintext,< / div >
< div class = "line" > < a name = "l00055" > < / a > < span class = "lineno" > 55< / span >   < span class = "keywordtype" > size_t< / span > * plaintext_size) {< / div >
< div class = "line" > < a name = "l00056" > < / a > < span class = "lineno" > 56< / span >   DCHECK(plaintext_size);< / div >
< div class = "line" > < a name = "l00057" > < / a > < span class = "lineno" > 57< / span >   DCHECK(aes_key());< / div >
< div class = "line" > < a name = "l00058" > < / a > < span class = "lineno" > 58< / span >   < span class = "comment" > // Plaintext size is the same as ciphertext size except for pkcs5 padding.< / span > < / div >
< div class = "line" > < a name = "l00059" > < / a > < span class = "lineno" > 59< / span >   < span class = "comment" > // Will update later if using pkcs5 padding. For pkcs5 padding, we still< / span > < / div >
< div class = "line" > < a name = "l00060" > < / a > < span class = "lineno" > 60< / span >   < span class = "comment" > // need at least |ciphertext_size| bytes for intermediate operation.< / span > < / div >
< div class = "line" > < a name = "l00061" > < / a > < span class = "lineno" > 61< / span >   < span class = "keywordflow" > if< / span > (*plaintext_size < ciphertext_size) {< / div >
< div class = "line" > < a name = "l00062" > < / a > < span class = "lineno" > 62< / span >   LOG(ERROR) < < < span class = "stringliteral" > " Expecting output size of at least " < / span > < < ciphertext_size< / div >
< div class = "line" > < a name = "l00063" > < / a > < span class = "lineno" > 63< / span >   < < < span class = "stringliteral" > " bytes." < / span > ;< / div >
< div class = "line" > < a name = "l00064" > < / a > < span class = "lineno" > 64< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > false< / span > ;< / div >
< div class = "line" > < a name = "l00065" > < / a > < span class = "lineno" > 65< / span >   }< / div >
< div class = "line" > < a name = "l00066" > < / a > < span class = "lineno" > 66< / span >   *plaintext_size = ciphertext_size;< / div >
< div class = "line" > < a name = "l00067" > < / a > < span class = "lineno" > 67< / span >   < / div >
< div class = "line" > < a name = "l00068" > < / a > < span class = "lineno" > 68< / span >   < span class = "keywordflow" > if< / span > (ciphertext_size == 0) {< / div >
< div class = "line" > < a name = "l00069" > < / a > < span class = "lineno" > 69< / span >   < span class = "keywordflow" > if< / span > (padding_scheme_ == kPkcs5Padding) {< / div >
< div class = "line" > < a name = "l00070" > < / a > < span class = "lineno" > 70< / span >   LOG(ERROR) < < < span class = "stringliteral" > " Expected ciphertext to be at least " < / span > < < AES_BLOCK_SIZE< / div >
< div class = "line" > < a name = "l00071" > < / a > < span class = "lineno" > 71< / span >   < < < span class = "stringliteral" > " bytes with Pkcs5 padding." < / span > ;< / div >
< div class = "line" > < a name = "l00072" > < / a > < span class = "lineno" > 72< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > false< / span > ;< / div >
< div class = "line" > < a name = "l00073" > < / a > < span class = "lineno" > 73< / span >   }< / div >
< div class = "line" > < a name = "l00074" > < / a > < span class = "lineno" > 74< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > true< / span > ;< / div >
< div class = "line" > < a name = "l00075" > < / a > < span class = "lineno" > 75< / span >   }< / div >
< div class = "line" > < a name = "l00076" > < / a > < span class = "lineno" > 76< / span >   DCHECK(plaintext);< / div >
< div class = "line" > < a name = "l00077" > < / a > < span class = "lineno" > 77< / span >   < / div >
< div class = "line" > < a name = "l00078" > < / a > < span class = "lineno" > 78< / span >   < span class = "keyword" > const< / span > < span class = "keywordtype" > size_t< / span > residual_block_size = ciphertext_size % AES_BLOCK_SIZE;< / div >
< div class = "line" > < a name = "l00079" > < / a > < span class = "lineno" > 79< / span >   < span class = "keyword" > const< / span > < span class = "keywordtype" > size_t< / span > cbc_size = ciphertext_size - residual_block_size;< / div >
< div class = "line" > < a name = "l00080" > < / a > < span class = "lineno" > 80< / span >   < span class = "keywordflow" > if< / span > (residual_block_size == 0) {< / div >
< div class = "line" > < a name = "l00081" > < / a > < span class = "lineno" > 81< / span >   AES_cbc_encrypt(ciphertext, plaintext, ciphertext_size, aes_key(),< / div >
< div class = "line" > < a name = "l00082" > < / a > < span class = "lineno" > 82< / span >   internal_iv_.data(), AES_DECRYPT);< / div >
< div class = "line" > < a name = "l00083" > < / a > < span class = "lineno" > 83< / span >   < span class = "keywordflow" > if< / span > (padding_scheme_ != kPkcs5Padding)< / div >
< div class = "line" > < a name = "l00084" > < / a > < span class = "lineno" > 84< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > true< / span > ;< / div >
< div class = "line" > < a name = "l00085" > < / a > < span class = "lineno" > 85< / span >   < / div >
< div class = "line" > < a name = "l00086" > < / a > < span class = "lineno" > 86< / span >   < span class = "comment" > // Strip off PKCS5 padding bytes.< / span > < / div >
< div class = "line" > < a name = "l00087" > < / a > < span class = "lineno" > 87< / span >   < span class = "keyword" > const< / span > uint8_t num_padding_bytes = plaintext[ciphertext_size - 1];< / div >
< div class = "line" > < a name = "l00088" > < / a > < span class = "lineno" > 88< / span >   < span class = "keywordflow" > if< / span > (num_padding_bytes > AES_BLOCK_SIZE) {< / div >
< div class = "line" > < a name = "l00089" > < / a > < span class = "lineno" > 89< / span >   LOG(ERROR) < < < span class = "stringliteral" > " Padding length is too large : " < / span > < / div >
< div class = "line" > < a name = "l00090" > < / a > < span class = "lineno" > 90< / span >   < < < span class = "keyword" > static_cast< < / span > < span class = "keywordtype" > int< / span > < span class = "keyword" > > < / span > (num_padding_bytes);< / div >
< div class = "line" > < a name = "l00091" > < / a > < span class = "lineno" > 91< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > false< / span > ;< / div >
< div class = "line" > < a name = "l00092" > < / a > < span class = "lineno" > 92< / span >   }< / div >
< div class = "line" > < a name = "l00093" > < / a > < span class = "lineno" > 93< / span >   *plaintext_size -= num_padding_bytes;< / div >
< div class = "line" > < a name = "l00094" > < / a > < span class = "lineno" > 94< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > true< / span > ;< / div >
< div class = "line" > < a name = "l00095" > < / a > < span class = "lineno" > 95< / span >   } < span class = "keywordflow" > else< / span > < span class = "keywordflow" > if< / span > (padding_scheme_ == kNoPadding) {< / div >
< div class = "line" > < a name = "l00096" > < / a > < span class = "lineno" > 96< / span >   AES_cbc_encrypt(ciphertext, plaintext, cbc_size, aes_key(),< / div >
< div class = "line" > < a name = "l00097" > < / a > < span class = "lineno" > 97< / span >   internal_iv_.data(), AES_DECRYPT);< / div >
< div class = "line" > < a name = "l00098" > < / a > < span class = "lineno" > 98< / span >   < / div >
< div class = "line" > < a name = "l00099" > < / a > < span class = "lineno" > 99< / span >   < span class = "comment" > // The residual block is not encrypted.< / span > < / div >
< div class = "line" > < a name = "l00100" > < / a > < span class = "lineno" > 100< / span >   memcpy(plaintext + cbc_size, ciphertext + cbc_size, residual_block_size);< / div >
< div class = "line" > < a name = "l00101" > < / a > < span class = "lineno" > 101< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > true< / span > ;< / div >
< div class = "line" > < a name = "l00102" > < / a > < span class = "lineno" > 102< / span >   } < span class = "keywordflow" > else< / span > < span class = "keywordflow" > if< / span > (padding_scheme_ != kCtsPadding) {< / div >
< div class = "line" > < a name = "l00103" > < / a > < span class = "lineno" > 103< / span >   LOG(ERROR) < < < span class = "stringliteral" > " Expecting cipher text size to be multiple of " < / span > < / div >
< div class = "line" > < a name = "l00104" > < / a > < span class = "lineno" > 104< / span >   < < AES_BLOCK_SIZE < < < span class = "stringliteral" > " , got " < / span > < < ciphertext_size;< / div >
< div class = "line" > < a name = "l00105" > < / a > < span class = "lineno" > 105< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > false< / span > ;< / div >
< div class = "line" > < a name = "l00106" > < / a > < span class = "lineno" > 106< / span >   }< / div >
< div class = "line" > < a name = "l00107" > < / a > < span class = "lineno" > 107< / span >   < / div >
< div class = "line" > < a name = "l00108" > < / a > < span class = "lineno" > 108< / span >   DCHECK_EQ(padding_scheme_, kCtsPadding);< / div >
< div class = "line" > < a name = "l00109" > < / a > < span class = "lineno" > 109< / span >   < span class = "keywordflow" > if< / span > (ciphertext_size < AES_BLOCK_SIZE) {< / div >
< div class = "line" > < a name = "l00110" > < / a > < span class = "lineno" > 110< / span >   < span class = "comment" > // Don' t have a full block, leave unencrypted.< / span > < / div >
< div class = "line" > < a name = "l00111" > < / a > < span class = "lineno" > 111< / span >   memcpy(plaintext, ciphertext, ciphertext_size);< / div >
< div class = "line" > < a name = "l00112" > < / a > < span class = "lineno" > 112< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > true< / span > ;< / div >
< div class = "line" > < a name = "l00113" > < / a > < span class = "lineno" > 113< / span >   }< / div >
< div class = "line" > < a name = "l00114" > < / a > < span class = "lineno" > 114< / span >   < / div >
< div class = "line" > < a name = "l00115" > < / a > < span class = "lineno" > 115< / span >   < span class = "comment" > // AES-CBC decrypt everything up to the next-to-last full block.< / span > < / div >
< div class = "line" > < a name = "l00116" > < / a > < span class = "lineno" > 116< / span >   < span class = "keywordflow" > if< / span > (cbc_size > AES_BLOCK_SIZE) {< / div >
< div class = "line" > < a name = "l00117" > < / a > < span class = "lineno" > 117< / span >   AES_cbc_encrypt(ciphertext, plaintext, cbc_size - AES_BLOCK_SIZE, aes_key(),< / div >
< div class = "line" > < a name = "l00118" > < / a > < span class = "lineno" > 118< / span >   internal_iv_.data(), AES_DECRYPT);< / div >
< div class = "line" > < a name = "l00119" > < / a > < span class = "lineno" > 119< / span >   }< / div >
< div class = "line" > < a name = "l00120" > < / a > < span class = "lineno" > 120< / span >   < / div >
< div class = "line" > < a name = "l00121" > < / a > < span class = "lineno" > 121< / span >   < span class = "keyword" > const< / span > uint8_t* next_to_last_ciphertext_block =< / div >
< div class = "line" > < a name = "l00122" > < / a > < span class = "lineno" > 122< / span >   ciphertext + ciphertext_size - residual_block_size - AES_BLOCK_SIZE;< / div >
< div class = "line" > < a name = "l00123" > < / a > < span class = "lineno" > 123< / span >   uint8_t* next_to_last_plaintext_block =< / div >
< div class = "line" > < a name = "l00124" > < / a > < span class = "lineno" > 124< / span >   plaintext + ciphertext_size - residual_block_size - AES_BLOCK_SIZE;< / div >
< div class = "line" > < a name = "l00125" > < / a > < span class = "lineno" > 125< / span >   < / div >
< div class = "line" > < a name = "l00126" > < / a > < span class = "lineno" > 126< / span >   < span class = "comment" > // Determine what the last IV should be so that we can " skip ahead" in the< / span > < / div >
< div class = "line" > < a name = "l00127" > < / a > < span class = "lineno" > 127< / span >   < span class = "comment" > // CBC decryption.< / span > < / div >
< div class = "line" > < a name = "l00128" > < / a > < span class = "lineno" > 128< / span >   std::vector< uint8_t> last_iv(< / div >
< div class = "line" > < a name = "l00129" > < / a > < span class = "lineno" > 129< / span >   ciphertext + ciphertext_size - residual_block_size,< / div >
< div class = "line" > < a name = "l00130" > < / a > < span class = "lineno" > 130< / span >   ciphertext + ciphertext_size);< / div >
< div class = "line" > < a name = "l00131" > < / a > < span class = "lineno" > 131< / span >   last_iv.resize(AES_BLOCK_SIZE, 0);< / div >
< div class = "line" > < a name = "l00132" > < / a > < span class = "lineno" > 132< / span >   < / div >
< div class = "line" > < a name = "l00133" > < / a > < span class = "lineno" > 133< / span >   < span class = "comment" > // Decrypt the next-to-last block using the IV determined above. This decrypts< / span > < / div >
< div class = "line" > < a name = "l00134" > < / a > < span class = "lineno" > 134< / span >   < span class = "comment" > // the residual block bits.< / span > < / div >
< div class = "line" > < a name = "l00135" > < / a > < span class = "lineno" > 135< / span >   AES_cbc_encrypt(next_to_last_ciphertext_block, next_to_last_plaintext_block,< / div >
< div class = "line" > < a name = "l00136" > < / a > < span class = "lineno" > 136< / span >   AES_BLOCK_SIZE, aes_key(), last_iv.data(), AES_DECRYPT);< / div >
< div class = "line" > < a name = "l00137" > < / a > < span class = "lineno" > 137< / span >   < / div >
< div class = "line" > < a name = "l00138" > < / a > < span class = "lineno" > 138< / span >   < span class = "comment" > // Swap back the residual block bits and the next-to-last block.< / span > < / div >
< div class = "line" > < a name = "l00139" > < / a > < span class = "lineno" > 139< / span >   < span class = "keywordflow" > if< / span > (plaintext == ciphertext) {< / div >
< div class = "line" > < a name = "l00140" > < / a > < span class = "lineno" > 140< / span >   std::swap_ranges(next_to_last_plaintext_block,< / div >
< div class = "line" > < a name = "l00141" > < / a > < span class = "lineno" > 141< / span >   next_to_last_plaintext_block + residual_block_size,< / div >
< div class = "line" > < a name = "l00142" > < / a > < span class = "lineno" > 142< / span >   next_to_last_plaintext_block + AES_BLOCK_SIZE);< / div >
< div class = "line" > < a name = "l00143" > < / a > < span class = "lineno" > 143< / span >   } < span class = "keywordflow" > else< / span > {< / div >
< div class = "line" > < a name = "l00144" > < / a > < span class = "lineno" > 144< / span >   memcpy(next_to_last_plaintext_block + AES_BLOCK_SIZE,< / div >
< div class = "line" > < a name = "l00145" > < / a > < span class = "lineno" > 145< / span >   next_to_last_plaintext_block, residual_block_size);< / div >
< div class = "line" > < a name = "l00146" > < / a > < span class = "lineno" > 146< / span >   memcpy(next_to_last_plaintext_block,< / div >
< div class = "line" > < a name = "l00147" > < / a > < span class = "lineno" > 147< / span >   next_to_last_ciphertext_block + AES_BLOCK_SIZE, residual_block_size);< / div >
< div class = "line" > < a name = "l00148" > < / a > < span class = "lineno" > 148< / span >   }< / div >
< div class = "line" > < a name = "l00149" > < / a > < span class = "lineno" > 149< / span >   < / div >
< div class = "line" > < a name = "l00150" > < / a > < span class = "lineno" > 150< / span >   < span class = "comment" > // Decrypt the next-to-last full block.< / span > < / div >
< div class = "line" > < a name = "l00151" > < / a > < span class = "lineno" > 151< / span >   AES_cbc_encrypt(next_to_last_plaintext_block, next_to_last_plaintext_block,< / div >
< div class = "line" > < a name = "l00152" > < / a > < span class = "lineno" > 152< / span >   AES_BLOCK_SIZE, aes_key(), internal_iv_.data(), AES_DECRYPT);< / div >
< div class = "line" > < a name = "l00153" > < / a > < span class = "lineno" > 153< / span >   < span class = "keywordflow" > return< / span > < span class = "keyword" > true< / span > ;< / div >
< div class = "line" > < a name = "l00154" > < / a > < span class = "lineno" > 154< / span >   }< / div >
< div class = "line" > < a name = "l00155" > < / a > < span class = "lineno" > 155< / span >   < / div >
< div class = "line" > < a name = "l00156" > < / a > < span class = "lineno" > 156< / span >   < span class = "keywordtype" > void< / span > AesCbcDecryptor::SetIvInternal() {< / div >
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< div class = "line" > < a name = "l00157" > < / a > < span class = "lineno" > 157< / span >   internal_iv_ = < a class = "code" href = "../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a96dde16f12a82a563c77f6d5522571f3" > iv< / a > ();< / div >
2016-04-20 21:57:59 +00:00
< div class = "line" > < a name = "l00158" > < / a > < span class = "lineno" > 158< / span >   internal_iv_.resize(AES_BLOCK_SIZE, 0);< / div >
< div class = "line" > < a name = "l00159" > < / a > < span class = "lineno" > 159< / span >   }< / div >
< div class = "line" > < a name = "l00160" > < / a > < span class = "lineno" > 160< / span >   < / div >
< div class = "line" > < a name = "l00161" > < / a > < span class = "lineno" > 161< / span >   } < span class = "comment" > // namespace media< / span > < / div >
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< div class = "line" > < a name = "l00162" > < / a > < span class = "lineno" > 162< / span >   } < span class = "comment" > // namespace shaka< / span > < / div >
< div class = "ttc" id = "classshaka_1_1media_1_1AesCryptor_html" > < div class = "ttname" > < a href = "../../df/d87/classshaka_1_1media_1_1AesCryptor.html" > shaka::media::AesCryptor< / a > < / div > < div class = "ttdef" > < b > Definition:< / b > < a href = "../../d0/d42/aes__cryptor_8h_source.html#l00025" > aes_cryptor.h:25< / a > < / div > < / div >
< div class = "ttc" id = "classshaka_1_1media_1_1AesCbcDecryptor_html" > < div class = "ttname" > < a href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html" > shaka::media::AesCbcDecryptor< / a > < / div > < div class = "ttdoc" > Class which implements AES-CBC (Cipher block chaining) decryption. < / div > < div class = "ttdef" > < b > Definition:< / b > < a href = "../../d8/d4d/aes__decryptor_8h_source.html#l00025" > aes_decryptor.h:25< / a > < / div > < / div >
< div class = "ttc" id = "classshaka_1_1media_1_1AesCbcDecryptor_html_a855ab9fa2f350879a7716ec90033f825" > < div class = "ttname" > < a href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a855ab9fa2f350879a7716ec90033f825" > shaka::media::AesCbcDecryptor::AesCbcDecryptor< / a > < / div > < div class = "ttdeci" > AesCbcDecryptor(CbcPaddingScheme padding_scheme)< / div > < div class = "ttdef" > < b > Definition:< / b > < a href = "../../da/df4/aes__decryptor_8cc_source.html#l00025" > aes_decryptor.cc:25< / a > < / div > < / div >
< div class = "ttc" id = "classshaka_1_1media_1_1AesCryptor_html_a96dde16f12a82a563c77f6d5522571f3" > < div class = "ttname" > < a href = "../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a96dde16f12a82a563c77f6d5522571f3" > shaka::media::AesCryptor::iv< / a > < / div > < div class = "ttdeci" > const std::vector< uint8_t > & iv() const < / div > < div class = "ttdef" > < b > Definition:< / b > < a href = "../../d0/d42/aes__cryptor_8h_source.html#l00081" > aes_cryptor.h:81< / a > < / div > < / div >
< div class = "ttc" id = "classshaka_1_1media_1_1AesCbcDecryptor_html_a71ff0b9654de96f9990b29c35fa9b7bf" > < div class = "ttname" > < a href = "../../df/d2d/classshaka_1_1media_1_1AesCbcDecryptor.html#a71ff0b9654de96f9990b29c35fa9b7bf" > shaka::media::AesCbcDecryptor::InitializeWithIv< / a > < / div > < div class = "ttdeci" > bool InitializeWithIv(const std::vector< uint8_t > & key, const std::vector< uint8_t > & iv) override< / div > < div class = "ttdef" > < b > Definition:< / b > < a href = "../../da/df4/aes__decryptor_8cc_source.html#l00040" > aes_decryptor.cc:40< / a > < / div > < / div >
2016-09-01 17:53:10 +00:00
< div class = "ttc" id = "classshaka_1_1media_1_1AesCryptor_html_a4875146da4761bb757d6b00132ae6fea" > < div class = "ttname" > < a href = "../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a4875146da4761bb757d6b00132ae6fea" > shaka::media::AesCryptor::SetIv< / a > < / div > < div class = "ttdeci" > bool SetIv(const std::vector< uint8_t > & iv)< / div > < div class = "ttdef" > < b > Definition:< / b > < a href = "../../d6/d55/aes__cryptor_8cc_source.html#l00067" > aes_cryptor.cc:67< / a > < / div > < / div >
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