1 // Copyright 2017 Google Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 /////////////////////////////////////////////////////////////////////////////// 16 17 #ifndef TINK_SUBTLE_ECIES_HKDF_RECIPIENT_KEM_BORINGSSL_H_ 18 #define TINK_SUBTLE_ECIES_HKDF_RECIPIENT_KEM_BORINGSSL_H_ 19 20 #include <memory> 21 22 #include "absl/strings/string_view.h" 23 #include "openssl/ec.h" 24 #include "openssl/evp.h" 25 #include "tink/internal/fips_utils.h" 26 #include "tink/internal/ssl_unique_ptr.h" 27 #include "tink/subtle/common_enums.h" 28 #include "tink/util/secret_data.h" 29 #include "tink/util/statusor.h" 30 31 namespace crypto { 32 namespace tink { 33 namespace subtle { 34 35 // HKDF-based KEM (key encapsulation mechanism) for ECIES recipient, 36 // using Boring SSL for the underlying cryptographic operations. 37 class EciesHkdfRecipientKemBoringSsl { 38 public: 39 // Constructs a recipient KEM for the specified curve and recipient's 40 // private key, which must be a big-endian byte array. 41 static crypto::tink::util::StatusOr< 42 std::unique_ptr<EciesHkdfRecipientKemBoringSsl>> 43 New(EllipticCurveType curve, util::SecretData priv_key); 44 45 // Computes the ecdh's shared secret from our private key and peer's encoded 46 // public key, then uses hkdf to derive the symmetric key from the shared 47 // secret, hkdf info and hkdf salt. 48 virtual crypto::tink::util::StatusOr<util::SecretData> GenerateKey( 49 absl::string_view kem_bytes, HashType hash, absl::string_view hkdf_salt, 50 absl::string_view hkdf_info, uint32_t key_size_in_bytes, 51 EcPointFormat point_format) const = 0; 52 53 virtual ~EciesHkdfRecipientKemBoringSsl() = default; 54 }; 55 56 // Implementation of EciesHkdfRecipientKemBoringSsl for the NIST P-curves. 57 class EciesHkdfNistPCurveRecipientKemBoringSsl 58 : public EciesHkdfRecipientKemBoringSsl { 59 public: 60 // Constructs a recipient KEM for the specified curve and recipient's 61 // private key, which must be a big-endian byte array. 62 static crypto::tink::util::StatusOr< 63 std::unique_ptr<EciesHkdfRecipientKemBoringSsl>> 64 New(EllipticCurveType curve, util::SecretData priv_key); 65 66 // Computes the ecdh's shared secret from our private key and peer's encoded 67 // public key, then uses hkdf to derive the symmetric key from the shared 68 // secret, hkdf info and hkdf salt. 69 crypto::tink::util::StatusOr<util::SecretData> GenerateKey( 70 absl::string_view kem_bytes, HashType hash, absl::string_view hkdf_salt, 71 absl::string_view hkdf_info, uint32_t key_size_in_bytes, 72 EcPointFormat point_format) const override; 73 74 static constexpr crypto::tink::internal::FipsCompatibility kFipsStatus = 75 crypto::tink::internal::FipsCompatibility::kNotFips; 76 77 private: 78 EciesHkdfNistPCurveRecipientKemBoringSsl( 79 EllipticCurveType curve, util::SecretData priv_key_value, 80 internal::SslUniquePtr<EC_GROUP> ec_group); 81 82 EllipticCurveType curve_; 83 util::SecretData priv_key_value_; 84 internal::SslUniquePtr<EC_GROUP> ec_group_; 85 }; 86 87 // Implementation of EciesHkdfRecipientKemBoringSsl for curve25519. 88 class EciesHkdfX25519RecipientKemBoringSsl 89 : public EciesHkdfRecipientKemBoringSsl { 90 public: 91 // Constructs a recipient KEM for the specified curve and recipient's 92 // private key, which must be a big-endian byte array. 93 static crypto::tink::util::StatusOr< 94 std::unique_ptr<EciesHkdfRecipientKemBoringSsl>> 95 New(EllipticCurveType curve, util::SecretData priv_key); 96 97 // Computes the ecdh's shared secret from our private key and peer's encoded 98 // public key, then uses hkdf to derive the symmetric key from the shared 99 // secret, hkdf info and hkdf salt. 100 crypto::tink::util::StatusOr<util::SecretData> GenerateKey( 101 absl::string_view kem_bytes, HashType hash, absl::string_view hkdf_salt, 102 absl::string_view hkdf_info, uint32_t key_size_in_bytes, 103 EcPointFormat point_format) const override; 104 105 static constexpr crypto::tink::internal::FipsCompatibility kFipsStatus = 106 crypto::tink::internal::FipsCompatibility::kNotFips; 107 108 private: 109 explicit EciesHkdfX25519RecipientKemBoringSsl( 110 internal::SslUniquePtr<EVP_PKEY> private_key); 111 112 const internal::SslUniquePtr<EVP_PKEY> private_key_; 113 }; 114 115 } // namespace subtle 116 } // namespace tink 117 } // namespace crypto 118 119 #endif // TINK_SUBTLE_ECIES_HKDF_RECIPIENT_KEM_BORINGSSL_H_ 120