CryptoSecretBoxer cleanup changes.

+ Keep the .h in sync with the internal source tree.
+ Moved encrypter_ and decrypter_ back to local variables in the Box and
  Unbox methods.
+ Fixed comments from wtc in https://codereview.chromium.org/213473003/

R=wtc@chromium.org

Review URL: https://codereview.chromium.org/257123002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266830 0039d316-1c4b-4281-b951-d872f2087c98

net/quic/crypto/crypto_secret_boxer.cc

@@ -5,7 +5,10 @@
 #include "net/quic/crypto/crypto_secret_boxer.h"
 
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "net/quic/crypto/crypto_protocol.h"
+#include "net/quic/crypto/quic_decrypter.h"
+#include "net/quic/crypto/quic_encrypter.h"
 #include "net/quic/crypto/quic_random.h"
 
 using base::StringPiece;
@@ -29,33 +32,21 @@ static const size_t kKeySize = 16;
 //   It's not terrible, but it's not a "forget about it" margin.
 static const size_t kBoxNonceSize = 12;
 
-CryptoSecretBoxer::CryptoSecretBoxer()
-    : encrypter_(QuicEncrypter::Create(kAESG)),
-      decrypter_(QuicDecrypter::Create(kAESG)) {
-}
-
-CryptoSecretBoxer::~CryptoSecretBoxer() {}
-
 // static
 size_t CryptoSecretBoxer::GetKeySize() { return kKeySize; }
 
-bool CryptoSecretBoxer::SetKey(StringPiece key) {
-  DCHECK_EQ(static_cast<size_t>(kKeySize), key.size());
-  string key_string = key.as_string();
-  if (!encrypter_->SetKey(key_string)) {
-    DLOG(DFATAL) << "CryptoSecretBoxer's encrypter_->SetKey failed.";
-    return false;
-  }
-  if (!decrypter_->SetKey(key_string)) {
-    DLOG(DFATAL) << "CryptoSecretBoxer's decrypter_->SetKey failed.";
-    return false;
-  }
-  return true;
+void CryptoSecretBoxer::SetKey(StringPiece key) {
+  DCHECK_EQ(kKeySize, key.size());
+  key_ = key.as_string();
 }
 
 string CryptoSecretBoxer::Box(QuicRandom* rand, StringPiece plaintext) const {
-  DCHECK_EQ(kKeySize, encrypter_->GetKeySize());
-  size_t ciphertext_size = encrypter_->GetCiphertextSize(plaintext.length());
+  scoped_ptr<QuicEncrypter> encrypter(QuicEncrypter::Create(kAESG));
+  if (!encrypter->SetKey(key_)) {
+    DLOG(DFATAL) << "CryptoSecretBoxer's encrypter->SetKey failed.";
+    return string();
+  }
+  size_t ciphertext_size = encrypter->GetCiphertextSize(plaintext.length());
 
   string ret;
   const size_t len = kBoxNonceSize + ciphertext_size;
@@ -66,7 +57,7 @@ string CryptoSecretBoxer::Box(QuicRandom* rand, StringPiece plaintext) const {
   rand->RandBytes(data, kBoxNonceSize);
   memcpy(data + kBoxNonceSize, plaintext.data(), plaintext.size());
 
-  if (!encrypter_->Encrypt(StringPiece(data, kBoxNonceSize), StringPiece(),
+  if (!encrypter->Encrypt(StringPiece(data, kBoxNonceSize), StringPiece(),
                           plaintext, reinterpret_cast<unsigned char*>(
                                          data + kBoxNonceSize))) {
     DLOG(DFATAL) << "CryptoSecretBoxer's Encrypt failed.";
@@ -91,7 +82,12 @@ bool CryptoSecretBoxer::Unbox(StringPiece ciphertext,
   out_storage->resize(len);
   char* data = const_cast<char*>(out_storage->data());
 
-  if (!decrypter_->Decrypt(StringPiece(nonce, kBoxNonceSize), StringPiece(),
+  scoped_ptr<QuicDecrypter> decrypter(QuicDecrypter::Create(kAESG));
+  if (!decrypter->SetKey(key_)) {
+    DLOG(DFATAL) << "CryptoSecretBoxer's decrypter->SetKey failed.";
+    return false;
+  }
+  if (!decrypter->Decrypt(StringPiece(nonce, kBoxNonceSize), StringPiece(),
                           ciphertext, reinterpret_cast<unsigned char*>(data),
                           &len)) {
     return false;

net/quic/crypto/crypto_secret_boxer.h

@@ -7,11 +7,8 @@
 
 #include <string>
 
-#include "base/memory/scoped_ptr.h"
 #include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
-#include "net/quic/crypto/quic_decrypter.h"
-#include "net/quic/crypto/quic_encrypter.h"
 
 namespace net {
 
@@ -22,17 +19,14 @@ class QuicRandom;
 // thread-safe.
 class NET_EXPORT_PRIVATE CryptoSecretBoxer {
  public:
-  // Initializes |encrypter_| and |decrypter_| data members.
-  CryptoSecretBoxer();
-  ~CryptoSecretBoxer();
+  CryptoSecretBoxer() {}
 
   // GetKeySize returns the number of bytes in a key.
   static size_t GetKeySize();
 
   // SetKey sets the key for this object. This must be done before |Box| or
-  // |Unbox| are called. |key| must be |GetKeySize()| bytes long. Returns false
-  // if |encrypter_| or |decrypter_|'s SetKey method fails.
-  bool SetKey(base::StringPiece key);
+  // |Unbox| are called. |key| must be |GetKeySize()| bytes long.
+  void SetKey(base::StringPiece key);
 
   // Box encrypts |plaintext| using a random nonce generated from |rand| and
   // returns the resulting ciphertext. Since an authenticator and nonce are
@@ -49,8 +43,7 @@ class NET_EXPORT_PRIVATE CryptoSecretBoxer {
              base::StringPiece* out) const;
 
  private:
-  scoped_ptr<QuicEncrypter> encrypter_;
-  scoped_ptr<QuicDecrypter> decrypter_;
+  std::string key_;
 
   DISALLOW_COPY_AND_ASSIGN(CryptoSecretBoxer);
 };