crypto/ec_private_key.h

   1 // Copyright (c) 2012 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 CRYPTO_EC_PRIVATE_KEY_H_
   6 #define CRYPTO_EC_PRIVATE_KEY_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "build/build_config.h"
  13 #include "crypto/crypto_export.h"
  14
  15 #if defined(USE_OPENSSL)
  16 // Forward declaration for openssl/*.h
  17 typedef struct evp_pkey_st EVP_PKEY;
  18 #else
  19 // Forward declaration.
  20 typedef struct CERTSubjectPublicKeyInfoStr CERTSubjectPublicKeyInfo;
  21 typedef struct SECKEYPrivateKeyStr SECKEYPrivateKey;
  22 typedef struct SECKEYPublicKeyStr SECKEYPublicKey;
  23 #endif
  24
  25 namespace crypto {
  26
  27 // Encapsulates an elliptic curve (EC) private key. Can be used to generate new
  28 // keys, export keys to other formats, or to extract a public key.
  29 // TODO(mattm): make this and RSAPrivateKey implement some PrivateKey interface.
  30 // (The difference in types of key() and public_key() make this a little
  31 // tricky.)
  32 class CRYPTO_EXPORT ECPrivateKey {
  33  public:
  34   ~ECPrivateKey();
  35
  36   // Returns whether the system supports elliptic curve cryptography.
  37   static bool IsSupported();
  38
  39   // Creates a new random instance. Can return NULL if initialization fails.
  40   // The created key will use the NIST P-256 curve.
  41   // TODO(mattm): Add a curve parameter.
  42   static ECPrivateKey* Create();
  43
  44   // Creates a new random instance. Can return NULL if initialization fails.
  45   // The created key is permanent and is not exportable in plaintext form.
  46   //
  47   // NOTE: Currently only available if USE_NSS is defined.
  48   static ECPrivateKey* CreateSensitive();
  49
  50   // Creates a new instance by importing an existing key pair.
  51   // The key pair is given as an ASN.1-encoded PKCS #8 EncryptedPrivateKeyInfo
  52   // block and an X.509 SubjectPublicKeyInfo block.
  53   // Returns NULL if initialization fails.
  54   static ECPrivateKey* CreateFromEncryptedPrivateKeyInfo(
  55       const std::string& password,
  56       const std::vector<uint8>& encrypted_private_key_info,
  57       const std::vector<uint8>& subject_public_key_info);
  58
  59   // Creates a new instance by importing an existing key pair.
  60   // The key pair is given as an ASN.1-encoded PKCS #8 EncryptedPrivateKeyInfo
  61   // block and an X.509 SubjectPublicKeyInfo block.
  62   // This can return NULL if initialization fails.  The created key is permanent
  63   // and is not exportable in plaintext form.
  64   //
  65   // NOTE: Currently only available if USE_NSS is defined.
  66   static ECPrivateKey* CreateSensitiveFromEncryptedPrivateKeyInfo(
  67       const std::string& password,
  68       const std::vector<uint8>& encrypted_private_key_info,
  69       const std::vector<uint8>& subject_public_key_info);
  70
  71 #if !defined(USE_OPENSSL)
  72   // Imports the key pair and returns in |public_key| and |key|.
  73   // Shortcut for code that needs to keep a reference directly to NSS types
  74   // without having to create a ECPrivateKey object and make a copy of them.
  75   // TODO(mattm): move this function to some NSS util file.
  76   static bool ImportFromEncryptedPrivateKeyInfo(
  77       const std::string& password,
  78       const uint8* encrypted_private_key_info,
  79       size_t encrypted_private_key_info_len,
  80       CERTSubjectPublicKeyInfo* decoded_spki,
  81       bool permanent,
  82       bool sensitive,
  83       SECKEYPrivateKey** key,
  84       SECKEYPublicKey** public_key);
  85 #endif
  86
  87 #if defined(USE_OPENSSL)
  88   EVP_PKEY* key() { return key_; }
  89 #else
  90   SECKEYPrivateKey* key() { return key_; }
  91   SECKEYPublicKey* public_key() { return public_key_; }
  92 #endif
  93
  94   // Exports the private key as an ASN.1-encoded PKCS #8 EncryptedPrivateKeyInfo
  95   // block and the public key as an X.509 SubjectPublicKeyInfo block.
  96   // The |password| and |iterations| are used as inputs to the key derivation
  97   // function for generating the encryption key.  PKCS #5 recommends a minimum
  98   // of 1000 iterations, on modern systems a larger value may be preferrable.
  99   bool ExportEncryptedPrivateKey(const std::string& password,
 100                                  int iterations,
 101                                  std::vector<uint8>* output);
 102
 103   // Exports the public key to an X.509 SubjectPublicKeyInfo block.
 104   bool ExportPublicKey(std::vector<uint8>* output);
 105
 106   // Exports private key data for testing. The format of data stored into output
 107   // doesn't matter other than that it is consistent for the same key.
 108   bool ExportValue(std::vector<uint8>* output);
 109   bool ExportECParams(std::vector<uint8>* output);
 110
 111  private:
 112   // Constructor is private. Use one of the Create*() methods above instead.
 113   ECPrivateKey();
 114
 115   // Shared helper for Create() and CreateSensitive().
 116   // TODO(cmasone): consider replacing |permanent| and |sensitive| with a
 117   //                flags arg created by ORing together some enumerated values.
 118   static ECPrivateKey* CreateWithParams(bool permanent,
 119                                         bool sensitive);
 120
 121   // Shared helper for CreateFromEncryptedPrivateKeyInfo() and
 122   // CreateSensitiveFromEncryptedPrivateKeyInfo().
 123   static ECPrivateKey* CreateFromEncryptedPrivateKeyInfoWithParams(
 124       const std::string& password,
 125       const std::vector<uint8>& encrypted_private_key_info,
 126       const std::vector<uint8>& subject_public_key_info,
 127       bool permanent,
 128       bool sensitive);
 129
 130 #if defined(USE_OPENSSL)
 131   EVP_PKEY* key_;
 132 #else
 133   SECKEYPrivateKey* key_;
 134   SECKEYPublicKey* public_key_;
 135 #endif
 136
 137   DISALLOW_COPY_AND_ASSIGN(ECPrivateKey);
 138 };
 139
 140
 141 }  // namespace crypto
 142
 143 #endif  // CRYPTO_EC_PRIVATE_KEY_H_