oblivious_http_response.cc | Explore in Territory

#include "quiche/oblivious_http/buffers/oblivious_http_response.h"

#include <stddef.h>
#include <stdint.h>

#include <algorithm>
#include <memory>
#include <string>
#include <utility>

#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "openssl/aead.h"
#include "openssl/hkdf.h"
#include "openssl/hpke.h"
#include "quiche/common/platform/api/quiche_bug_tracker.h"
#include "quiche/common/quiche_crypto_logging.h"
#include "quiche/common/quiche_random.h"
#include "quiche/oblivious_http/common/oblivious_http_header_key_config.h"

namespace quiche {
namespace {
// Generate a random string.
void random(QuicheRandom* quiche_random, char* dest, size_t len) { … }
}  // namespace

// Ctor.
ObliviousHttpResponse::ObliviousHttpResponse(std::string encrypted_data,
                                             std::string resp_plaintext)
    : … { … }

// Response Decapsulation.
// 1. Extract resp_nonce
// 2. Build prk (pseudorandom key) using HKDF_Extract
// 3. Derive aead_key using HKDF_Labeled_Expand
// 4. Derive aead_nonce using HKDF_Labeled_Expand
// 5. Setup AEAD context and Decrypt.
// https://www.ietf.org/archive/id/draft-ietf-ohai-ohttp-03.html#section-4.2-4
absl::StatusOr<ObliviousHttpResponse>
ObliviousHttpResponse::CreateClientObliviousResponse(
    std::string encrypted_data,
    ObliviousHttpRequest::Context& oblivious_http_request_context,
    absl::string_view resp_label) { … }

// Response Encapsulation.
// Follows the Ohttp spec section-4.2 (Encapsulation of Responses) Ref
// https://www.ietf.org/archive/id/draft-ietf-ohai-ohttp-03.html#section-4.2
// Use HPKE context from BoringSSL to export a secret and use it to Seal (AKA
// encrypt) the response back to the Sender(client)
absl::StatusOr<ObliviousHttpResponse>
ObliviousHttpResponse::CreateServerObliviousResponse(
    std::string plaintext_payload,
    ObliviousHttpRequest::Context& oblivious_http_request_context,
    absl::string_view response_label, QuicheRandom* quiche_random) { … }

// Serialize.
// enc_response = concat(response_nonce, ct)
// https://www.ietf.org/archive/id/draft-ietf-ohai-ohttp-03.html#section-4.2-4
const std::string& ObliviousHttpResponse::EncapsulateAndSerialize() const { … }

// Decrypted blob.
const std::string& ObliviousHttpResponse::GetPlaintextData() const { … }

// This section mainly deals with common operations performed by both
// Sender(client) and Receiver(gateway) on ObliviousHttpResponse.

absl::StatusOr<ObliviousHttpResponse::CommonAeadParamsResult>
ObliviousHttpResponse::GetCommonAeadParams(
    ObliviousHttpRequest::Context& oblivious_http_request_context) { … }

// Common Steps of AEAD key and AEAD nonce derivation common to both
// client(decapsulation) & Gateway(encapsulation) in handling
// Oblivious-Response. Ref Steps (1, 3-to-5, and setting up AEAD context in
// preparation for 6th step's Seal/Open) in spec.
// https://www.ietf.org/archive/id/draft-ietf-ohai-ohttp-03.html#section-4.2-4
absl::StatusOr<ObliviousHttpResponse::CommonOperationsResult>
ObliviousHttpResponse::CommonOperationsToEncapDecap(
    absl::string_view response_nonce,
    ObliviousHttpRequest::Context& oblivious_http_request_context,
    absl::string_view resp_label, const size_t aead_key_len,
    const size_t aead_nonce_len, const size_t secret_len) { … }

}  // namespace quiche
chromium/net/third_party/quiche/src/quiche/oblivious_http/buffers/oblivious_http_response.cc
