Add PKCS#8 ECPrivateKey export/import functions.

crypto/ec_private_key.h

 // 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.
 
 #ifndef CRYPTO_EC_PRIVATE_KEY_H_
 #define CRYPTO_EC_PRIVATE_KEY_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
+#include <memory>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "crypto/crypto_export.h"
 
 // Forward declaration for openssl/*.h
 typedef struct evp_pkey_st EVP_PKEY;
 
 namespace crypto {
 
 // Encapsulates an elliptic curve (EC) private key. Can be used to generate new
 // keys, export keys to other formats, or to extract a public key.
 // TODO(mattm): make this and RSAPrivateKey implement some PrivateKey interface.
 // (The difference in types of key() and public_key() make this a little
 // tricky.)
 class CRYPTO_EXPORT ECPrivateKey {
  public:
   ~ECPrivateKey();
 
   // Creates a new random instance. Can return NULL if initialization fails.
   // The created key will use the NIST P-256 curve.
   // TODO(mattm): Add a curve parameter.
   static ECPrivateKey* Create();
 
+  // Create a new instance by importing an existing private key. The format is
+  // an ASN.1-encoded PrivateKeyInfo block from PKCS #8. This can return
+  // nullptr if initialization fails.
+  static std::unique_ptr<ECPrivateKey> CreateFromPrivateKeyInfo(
+      const std::vector<uint8_t>& input);
+
   // Creates a new instance by importing an existing key pair.
   // The key pair is given as an ASN.1-encoded PKCS #8 EncryptedPrivateKeyInfo
   // block and an X.509 SubjectPublicKeyInfo block.
   // Returns NULL if initialization fails.
+  //
+  // This function is deprecated. Use CreateFromPrivateKeyInfo for new code.
+  // See https://crbug.com/603319.
   static ECPrivateKey* CreateFromEncryptedPrivateKeyInfo(
       const std::string& password,
       const std::vector<uint8_t>& encrypted_private_key_info,
       const std::vector<uint8_t>& subject_public_key_info);
 
   // Returns a copy of the object.
   ECPrivateKey* Copy() const;
 
   EVP_PKEY* key() { return key_; }
 
+  // Exports the private key to a PKCS #8 PrivateKeyInfo block.
+  bool ExportPrivateKey(std::vector<uint8_t>* output) const;
+
   // Exports the private key as an ASN.1-encoded PKCS #8 EncryptedPrivateKeyInfo
   // block and the public key as an X.509 SubjectPublicKeyInfo block.
   // The |password| and |iterations| are used as inputs to the key derivation
   // function for generating the encryption key.  PKCS #5 recommends a minimum
   // of 1000 iterations, on modern systems a larger value may be preferrable.
+  //
+  // This function is deprecated. Use ExportPrivateKey for new code. See
+  // https://crbug.com/603319.
   bool ExportEncryptedPrivateKey(const std::string& password,
                                  int iterations,
-                                 std::vector<uint8_t>* output);
+                                 std::vector<uint8_t>* output) const;
 
   // Exports the public key to an X.509 SubjectPublicKeyInfo block.
-  bool ExportPublicKey(std::vector<uint8_t>* output);
+  bool ExportPublicKey(std::vector<uint8_t>* output) const;
 
   // Exports the public key as an EC point in the uncompressed point format.
-  bool ExportRawPublicKey(std::string* output);
-
-  // Exports private key data for testing. The format of data stored into output
-  // doesn't matter other than that it is consistent for the same key.
-  bool ExportValueForTesting(std::vector<uint8_t>* output);
+  bool ExportRawPublicKey(std::string* output) const;
 
  private:
   // Constructor is private. Use one of the Create*() methods above instead.
   ECPrivateKey();
 
   EVP_PKEY* key_;
 
   DISALLOW_COPY_AND_ASSIGN(ECPrivateKey);
 };
 
 
 }  // namespace crypto
 
 #endif  // CRYPTO_EC_PRIVATE_KEY_H_