Export media_cas_packager_sdk

common/ecb_util.cc

@@ -0,0 +1,113 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright 2016 Google LLC.
+//
+// This software is licensed under the terms defined in the Widevine Master
+// License Agreement. For a copy of this agreement, please contact
+// widevine-licensing@google.com.
+////////////////////////////////////////////////////////////////////////////////
+
+// Implementation of ecb crypto routines used by Widevine services.
+
+#include "common/ecb_util.h"
+
+#include "glog/logging.h"
+#include "absl/strings/string_view.h"
+#include "openssl/aes.h"
+#include "openssl/des.h"
+
+namespace widevine {
+namespace crypto_util {
+
+const int kWvmDESKeySizeBytes = 16;
+
+static bool EncryptOrDecrypt3DesCbc(absl::string_view key,
+                                    absl::string_view src, std::string* dst,
+                                    bool encrypt) {
+  CHECK(dst);
+  if (key.size() != kWvmDESKeySizeBytes) {
+    LOG(WARNING) << "Invalid 3DES key size (" << key.size() << "!=16).";
+    dst->clear();
+    return false;
+  }
+  const int data_size = src.size();
+  if (data_size % DES_KEY_SZ != 0) {
+    // Data must be a multiple of block size
+    LOG(WARNING) << "3DES data is not a multiple of 8 bytes.";
+    dst->clear();
+    return false;
+  }
+  const int data_size_blocks = data_size / DES_KEY_SZ;
+  DES_key_schedule schedule[2];
+  // const_DES_cblock (the type of the first argument to DES_ecb3_encrypt) isn't
+  // actually const, so we have to cast away const.
+  DES_cblock* keyblock =
+      const_cast<DES_cblock*>(reinterpret_cast<const DES_cblock*>(key.data()));
+  DES_set_key(keyblock + 0, schedule + 1);
+  DES_set_key(keyblock + 1, schedule + 0);
+  DES_cblock* srcblock =
+      const_cast<DES_cblock*>(reinterpret_cast<const DES_cblock*>(src.data()));
+  dst->resize(data_size);
+  DES_cblock* dstblock = reinterpret_cast<DES_cblock*>(&*dst->begin());
+  for (int i = 0; i < data_size_blocks; i++) {
+    DES_ecb3_encrypt(srcblock + i, dstblock + i, schedule + 0, schedule + 1,
+                     schedule + 0, encrypt);
+  }
+  return true;
+}
+
+bool Encrypt3DesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
+  return EncryptOrDecrypt3DesCbc(key, src, dst, DES_ENCRYPT);
+}
+
+bool Decrypt3DesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
+  return EncryptOrDecrypt3DesCbc(key, src, dst, DES_DECRYPT);
+}
+
+bool EncryptAesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
+  CHECK(dst);
+  dst->clear();
+  if (src.size() % 16 != 0) {
+    LOG(WARNING) << "AES-ECB data is not a multiple of 16 bytes.";
+    return false;
+  }
+  int num_bits = key.size() * 8;
+  AES_KEY aes_key;
+  int aes_result = AES_set_encrypt_key(
+      reinterpret_cast<const uint8_t*>(key.data()), num_bits, &aes_key);
+  if (aes_result != 0) {
+    LOG(WARNING) << "AES result is not zero.";
+    return false;
+  }
+  dst->resize(src.size());
+  for (int i = 0; i < src.size(); i += AES_BLOCK_SIZE) {
+    AES_encrypt(reinterpret_cast<const uint8_t*>(src.data()+i),
+                reinterpret_cast<uint8_t*>(&(*dst)[i]), &aes_key);
+  }
+  return true;
+}
+
+bool DecryptAesEcb(absl::string_view key, absl::string_view src, std::string* dst) {
+  CHECK(dst);
+  dst->clear();
+  if (src.size() % 16 != 0) {
+    LOG(WARNING) << "AES-ECB data is not a multiple of 16 bytes.";
+    return false;
+  }
+  int num_bits = key.size() * 8;
+  AES_KEY aes_key;
+  int aes_result = AES_set_decrypt_key(
+      reinterpret_cast<const uint8_t*>(key.data()), num_bits, &aes_key);
+  if (aes_result != 0) {
+    LOG(WARNING) << "AES result is not zero.";
+    return false;
+  }
+  dst->resize(src.size());
+  for (int i = 0; i < src.size(); i += AES_BLOCK_SIZE) {
+    AES_decrypt(reinterpret_cast<const uint8_t*>(src.data()+i),
+                reinterpret_cast<uint8_t*>(&(*dst)[i]), &aes_key);
+  }
+  return true;
+}
+
+}  // namespace crypto_util
+}  // namespace widevine