114 lines
3.8 KiB
C++
114 lines
3.8 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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// Copyright 2016 Google LLC.
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//
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// This software is licensed under the terms defined in the Widevine Master
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// License Agreement. For a copy of this agreement, please contact
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// widevine-licensing@google.com.
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////////////////////////////////////////////////////////////////////////////////
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// Implementation of ecb crypto routines used by Widevine services.
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#include "common/ecb_util.h"
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#include "glog/logging.h"
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#include "absl/strings/string_view.h"
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#include "openssl/aes.h"
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#include "openssl/des.h"
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namespace widevine {
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namespace crypto_util {
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const int kWvmDESKeySizeBytes = 16;
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static bool EncryptOrDecrypt3DesCbc(absl::string_view key,
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absl::string_view src, std::string* dst,
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bool encrypt) {
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CHECK(dst);
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if (key.size() != kWvmDESKeySizeBytes) {
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LOG(WARNING) << "Invalid 3DES key size (" << key.size() << "!=16).";
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dst->clear();
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return false;
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}
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const int data_size = src.size();
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if (data_size % DES_KEY_SZ != 0) {
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// Data must be a multiple of block size
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LOG(WARNING) << "3DES data is not a multiple of 8 bytes.";
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dst->clear();
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return false;
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}
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const int data_size_blocks = data_size / DES_KEY_SZ;
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DES_key_schedule schedule[2];
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// const_DES_cblock (the type of the first argument to DES_ecb3_encrypt) isn't
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// actually const, so we have to cast away const.
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DES_cblock* keyblock =
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const_cast<DES_cblock*>(reinterpret_cast<const DES_cblock*>(key.data()));
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DES_set_key(keyblock + 0, schedule + 1);
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DES_set_key(keyblock + 1, schedule + 0);
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DES_cblock* srcblock =
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const_cast<DES_cblock*>(reinterpret_cast<const DES_cblock*>(src.data()));
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dst->resize(data_size);
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DES_cblock* dstblock = reinterpret_cast<DES_cblock*>(&*dst->begin());
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for (int i = 0; i < data_size_blocks; i++) {
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DES_ecb3_encrypt(srcblock + i, dstblock + i, schedule + 0, schedule + 1,
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schedule + 0, encrypt);
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}
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return true;
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}
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bool Encrypt3DesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
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return EncryptOrDecrypt3DesCbc(key, src, dst, DES_ENCRYPT);
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}
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bool Decrypt3DesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
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return EncryptOrDecrypt3DesCbc(key, src, dst, DES_DECRYPT);
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}
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bool EncryptAesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
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CHECK(dst);
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dst->clear();
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if (src.size() % 16 != 0) {
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LOG(WARNING) << "AES-ECB data is not a multiple of 16 bytes.";
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return false;
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}
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int num_bits = key.size() * 8;
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AES_KEY aes_key;
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int aes_result = AES_set_encrypt_key(
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reinterpret_cast<const uint8_t*>(key.data()), num_bits, &aes_key);
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if (aes_result != 0) {
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LOG(WARNING) << "AES result is not zero.";
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return false;
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}
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dst->resize(src.size());
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for (int i = 0; i < src.size(); i += AES_BLOCK_SIZE) {
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AES_encrypt(reinterpret_cast<const uint8_t*>(src.data() + i),
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reinterpret_cast<uint8_t*>(&(*dst)[i]), &aes_key);
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}
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return true;
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}
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bool DecryptAesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
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CHECK(dst);
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dst->clear();
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if (src.size() % 16 != 0) {
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LOG(WARNING) << "AES-ECB data is not a multiple of 16 bytes.";
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return false;
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}
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int num_bits = key.size() * 8;
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AES_KEY aes_key;
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int aes_result = AES_set_decrypt_key(
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reinterpret_cast<const uint8_t*>(key.data()), num_bits, &aes_key);
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if (aes_result != 0) {
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LOG(WARNING) << "AES result is not zero.";
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return false;
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}
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dst->resize(src.size());
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for (int i = 0; i < src.size(); i += AES_BLOCK_SIZE) {
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AES_decrypt(reinterpret_cast<const uint8_t*>(src.data() + i),
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reinterpret_cast<uint8_t*>(&(*dst)[i]), &aes_key);
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}
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return true;
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}
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} // namespace crypto_util
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} // namespace widevine
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