// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_
#define NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
#include "net/quic/crypto/common_cert_set.h"
#include "net/quic/crypto/crypto_protocol.h"
namespace net {
// CertCompressor provides functions for compressing and decompressing
// certificate chains using three techniquies:
// 1) The peer may provide a list of a 64-bit, FNV-1a hashes of certificates
// that they already have. In the event that one of them is to be
// compressed, it can be replaced with just the hash.
// 2) The peer may provide a number of hashes that represent sets of
// pre-shared certificates (CommonCertSets). If one of those certificates
// is to be compressed, and it's known to the given CommonCertSets, then it
// can be replaced with a set hash and certificate index.
// 3) Otherwise the certificates are compressed with zlib using a pre-shared
// dictionary that consists of the certificates handled with the above
// methods and a small chunk of common substrings.
class NET_EXPORT_PRIVATE CertCompressor {
public:
// CompressChain compresses the certificates in |certs| and returns a
// compressed representation. |common_sets| contains the common certificate
// sets known locally and |client_common_set_hashes| contains the hashes of
// the common sets known to the peer. |client_cached_cert_hashes| contains
// 64-bit, FNV-1a hashes of certificates that the peer already possesses.
static std::string CompressChain(const std::vector<std::string>& certs,
base::StringPiece client_common_set_hashes,
base::StringPiece client_cached_cert_hashes,
const CommonCertSets* common_sets);
// DecompressChain decompresses the result of |CompressChain|, given in |in|,
// into a series of certificates that are written to |out_certs|.
// |cached_certs| contains certificates that the peer may have omitted and
// |common_sets| contains the common certificate sets known locally.
static bool DecompressChain(base::StringPiece in,
const std::vector<std::string>& cached_certs,
const CommonCertSets* common_sets,
std::vector<std::string>* out_certs);
};
} // namespace net
#endif // NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_