1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_ 6 #define NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "base/basictypes.h" 12 #include "base/strings/string_piece.h" 13 #include "net/base/net_export.h" 14 #include "net/quic/crypto/common_cert_set.h" 15 #include "net/quic/crypto/crypto_protocol.h" 16 17 namespace net { 18 19 // CertCompressor provides functions for compressing and decompressing 20 // certificate chains using three techniquies: 21 // 1) The peer may provide a list of a 64-bit, FNV-1a hashes of certificates 22 // that they already have. In the event that one of them is to be 23 // compressed, it can be replaced with just the hash. 24 // 2) The peer may provide a number of hashes that represent sets of 25 // pre-shared certificates (CommonCertSets). If one of those certificates 26 // is to be compressed, and it's known to the given CommonCertSets, then it 27 // can be replaced with a set hash and certificate index. 28 // 3) Otherwise the certificates are compressed with zlib using a pre-shared 29 // dictionary that consists of the certificates handled with the above 30 // methods and a small chunk of common substrings. 31 class NET_EXPORT_PRIVATE CertCompressor { 32 public: 33 // CompressChain compresses the certificates in |certs| and returns a 34 // compressed representation. |common_sets| contains the common certificate 35 // sets known locally and |client_common_set_hashes| contains the hashes of 36 // the common sets known to the peer. |client_cached_cert_hashes| contains 37 // 64-bit, FNV-1a hashes of certificates that the peer already possesses. 38 static std::string CompressChain(const std::vector<std::string>& certs, 39 base::StringPiece client_common_set_hashes, 40 base::StringPiece client_cached_cert_hashes, 41 const CommonCertSets* common_sets); 42 43 // DecompressChain decompresses the result of |CompressChain|, given in |in|, 44 // into a series of certificates that are written to |out_certs|. 45 // |cached_certs| contains certificates that the peer may have omitted and 46 // |common_sets| contains the common certificate sets known locally. 47 static bool DecompressChain(base::StringPiece in, 48 const std::vector<std::string>& cached_certs, 49 const CommonCertSets* common_sets, 50 std::vector<std::string>* out_certs); 51 52 private: 53 DISALLOW_COPY_AND_ASSIGN(CertCompressor); 54 }; 55 56 } // namespace net 57 58 #endif // NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_ 59
