QUIC: support diversified keys with version 33.

net/quic/crypto/quic_decrypter.cc

 // Copyright (c) 2012 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.
 
 #include "net/quic/crypto/quic_decrypter.h"
 
+#include "crypto/hkdf.h"
 #include "net/quic/crypto/aes_128_gcm_12_decrypter.h"
 #include "net/quic/crypto/chacha20_poly1305_rfc7539_decrypter.h"
 #include "net/quic/crypto/crypto_protocol.h"
 #include "net/quic/crypto/null_decrypter.h"
 
+using base::StringPiece;
+using std::string;
+
 namespace net {
 
 // static
 QuicDecrypter* QuicDecrypter::Create(QuicTag algorithm) {
   switch (algorithm) {
     case kAESG:
       return new Aes128Gcm12Decrypter();
     case kCC20:
       return new ChaCha20Poly1305Rfc7539Decrypter();
     case kNULL:
       return new NullDecrypter();
     default:
       LOG(FATAL) << "Unsupported algorithm: " << algorithm;
       return nullptr;
   }
 }
 
+// static
+void QuicDecrypter::DiversifyPreliminaryKey(StringPiece preliminary_key,
+                                            StringPiece nonce_prefix,
+                                            DiversificationNonce nonce,
+                                            size_t key_size,
+                                            size_t nonce_prefix_size,
+                                            string* out_key,
+                                            string* out_nonce_prefix) {
+  crypto::HKDF hkdf(preliminary_key.as_string() + nonce_prefix.as_string(),
+                    StringPiece(nonce, kDiversificationNonceSize),
+                    "QUIC key diversification", 0, key_size, 0,
+                    nonce_prefix_size, 0);
+  *out_key = hkdf.server_write_key().as_string();
+  *out_nonce_prefix = hkdf.server_write_iv().as_string();
+}
+
 }  // namespace net