////////////////////////////////////////////////////////////////////////////////
// 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.
////////////////////////////////////////////////////////////////////////////////

#include "common/signing_key_util.h"

#include "glog/logging.h"
#include "common/crypto_util.h"
#include "protos/public/license_protocol.pb.h"

namespace widevine {

using crypto_util::kSigningKeySizeBits;

uint32_t SigningKeyMaterialSizeBits(ProtocolVersion protocol_version) {
  if (protocol_version <= VERSION_2_0) {
    return kSigningKeySizeBits;
  } else {
    return kSigningKeySizeBits * 2;
  }
}

using crypto_util::kSigningKeySizeBytes;
std::string GetClientSigningKey(const std::string& derived_key,
                           ProtocolVersion protocol_version) {
  if (protocol_version == VERSION_2_0) {
    DCHECK(derived_key.size() >= kSigningKeySizeBytes);
    return derived_key.substr(0, kSigningKeySizeBytes);
  } else {
    DCHECK(derived_key.size() >= kSigningKeySizeBytes * 2);
    return derived_key.substr(kSigningKeySizeBytes, kSigningKeySizeBytes);
  }
}

std::string GetServerSigningKey(const std::string& derived_key) {
  DCHECK(derived_key.size() >= kSigningKeySizeBytes);
  return derived_key.substr(0, kSigningKeySizeBytes);
}

}  // namespace widevine