Revisit CCF crypto interfaces (mostly RSA/EC keys) (#7425)

Co-authored-by: Copilot <[email protected]>
Co-authored-by: Amaury Chamayou <[email protected]>
Co-authored-by: Amaury Chamayou <[email protected]>

Author: 3 people

CHANGELOG.md

@@ -16,6 +16,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Changed
 
 - When the `fetch_recent_snapshot` behaviour is enabled by the node config, the Joiner will now prefer the peer's snapshot over _any_ local snapshot, regardless of version (#7314).
+- Crypto interface for RSA and EC keys (#7425)
+  - `ccf::crypto::PublicKey` becomes `ccf::crypto::ECPublicKey`
+  - `ccf::crypto::KeyPair` becomes `ccf::crypto::ECKeyPair`
+  - Error-prone inheritance between RSA and EC key classes has been removed.
+  - RSA keys now don't re-use CSR functionality from EC key interface.
 
 ### Removed
 

cmake/crypto.cmake

@@ -7,18 +7,16 @@ set(CCFCRYPTO_SRC
     ${CCF_DIR}/src/crypto/hash.cpp
     ${CCF_DIR}/src/crypto/sha256_hash.cpp
     ${CCF_DIR}/src/crypto/symmetric_key.cpp
-    ${CCF_DIR}/src/crypto/key_pair.cpp
     ${CCF_DIR}/src/crypto/eddsa_key_pair.cpp
-    ${CCF_DIR}/src/crypto/rsa_key_pair.cpp
     ${CCF_DIR}/src/crypto/verifier.cpp
     ${CCF_DIR}/src/crypto/key_wrap.cpp
     ${CCF_DIR}/src/crypto/hmac.cpp
     ${CCF_DIR}/src/crypto/pem.cpp
     ${CCF_DIR}/src/crypto/ecdsa.cpp
     ${CCF_DIR}/src/crypto/cose.cpp
     ${CCF_DIR}/src/crypto/openssl/symmetric_key.cpp
-    ${CCF_DIR}/src/crypto/openssl/public_key.cpp
-    ${CCF_DIR}/src/crypto/openssl/key_pair.cpp
+    ${CCF_DIR}/src/crypto/openssl/ec_public_key.cpp
+    ${CCF_DIR}/src/crypto/openssl/ec_key_pair.cpp
     ${CCF_DIR}/src/crypto/openssl/eddsa_public_key.cpp
     ${CCF_DIR}/src/crypto/openssl/eddsa_key_pair.cpp
     ${CCF_DIR}/src/crypto/openssl/hash.cpp

doc/build_apps/crypto.rst

@@ -25,16 +25,16 @@ Hashing
 Asymmetric Keys
 -----------------------
 
-CCF supports EC and RSA keys; public keys are held in (RSA)PublicKey objects and
-private keys in (RSA)KeyPair objects. (RSA)KeyPairs automatically generate random
-keys when constructed via :cpp:func:`KeyPairPtr ccf::crypto::make_key_pair(CurveID)` or
+CCF supports EC and RSA keys; public keys are held in [RSA|EC]PublicKey objects and
+private keys in [RSA|EC]KeyPair objects. [RSA|EC]KeyPair automatically generate random
+keys when constructed via :cpp:func:`ECKeyPairPtr ccf::crypto::make_ec_key_pair(CurveID)` or
 :cpp:func:`RSAKeyPairPtr ccf::crypto::make_rsa_key_pair(size_t, size_t)`.
 
-.. doxygenclass:: ccf::crypto::PublicKey
+.. doxygenclass:: ccf::crypto::ECPublicKey
   :project: CCF
   :members:
 
-.. doxygenclass:: ccf::crypto::KeyPair
+.. doxygenclass:: ccf::crypto::ECKeyPair
   :project: CCF
   :members:
 
@@ -49,10 +49,10 @@ keys when constructed via :cpp:func:`KeyPairPtr ccf::crypto::make_key_pair(Curve
 .. doxygenenum:: ccf::crypto::CurveID
   :project: CCF
 
-.. doxygenfunction:: ccf::crypto::make_key_pair(CurveID)
+.. doxygenfunction:: ccf::crypto::make_ec_key_pair(CurveID)
   :project: CCF
 
-.. doxygenfunction:: ccf::crypto::make_key_pair(const Pem&)
+.. doxygenfunction:: ccf::crypto::make_ec_key_pair(const Pem&)
   :project: CCF
 
 .. doxygenfunction:: ccf::crypto::make_rsa_key_pair(size_t, size_t)

include/ccf/crypto/cose_verifier.h

@@ -2,10 +2,7 @@
 // Licensed under the Apache 2.0 License.
 #pragma once
 
-#include "ccf/crypto/key_pair.h"
-#include "ccf/crypto/pem.h"
-#include "ccf/crypto/public_key.h"
-#include "ccf/crypto/rsa_key_pair.h"
+#include "ccf/crypto/verifier.h"
 
 #include <chrono>
 

include/ccf/crypto/key_pair.h renamed to include/ccf/crypto/ec_key_pair.h

@@ -3,9 +3,9 @@
 #pragma once
 
 #include "ccf/crypto/curve.h"
+#include "ccf/crypto/ec_public_key.h"
 #include "ccf/crypto/jwk.h"
 #include "ccf/crypto/pem.h"
-#include "ccf/crypto/public_key.h"
 #include "ccf/crypto/san.h"
 
 #include <cstdint>
@@ -15,10 +15,10 @@
 
 namespace ccf::crypto
 {
-  class KeyPair
+  class ECKeyPair
   {
   public:
-    virtual ~KeyPair() = default;
+    virtual ~ECKeyPair() = default;
 
     [[nodiscard]] virtual Pem private_key_pem() const = 0;
     [[nodiscard]] virtual Pem public_key_pem() const = 0;
@@ -129,44 +129,19 @@ namespace ccf::crypto
     }
 
     virtual std::vector<uint8_t> derive_shared_secret(
-      const PublicKey& peer_key) = 0;
+      const ECPublicKey& peer_key) = 0;
 
     [[nodiscard]] virtual std::vector<uint8_t> public_key_raw() const = 0;
 
     [[nodiscard]] virtual CurveID get_curve_id() const = 0;
 
-    [[nodiscard]] virtual PublicKey::Coordinates coordinates() const = 0;
+    [[nodiscard]] virtual ECPublicKey::Coordinates coordinates() const = 0;
 
     [[nodiscard]] virtual JsonWebKeyECPrivate private_key_jwk(
       const std::optional<std::string>& kid = std::nullopt) const = 0;
   };
 
-  using PublicKeyPtr = std::shared_ptr<PublicKey>;
-  using KeyPairPtr = std::shared_ptr<KeyPair>;
-
-  /**
-   * Construct PublicKey from a raw public key in PEM format
-   *
-   * @param pem Sequence of bytes containing the key in PEM format
-   * @return Public key
-   */
-  PublicKeyPtr make_public_key(const Pem& pem);
-
-  /**
-   * Construct PublicKey from a raw public key in DER format
-   *
-   * @param der Sequence of bytes containing the key in DER format
-   * @return Public key
-   */
-  PublicKeyPtr make_public_key(const std::vector<uint8_t>& der);
-
-  /**
-   * Construct PublicKey from a JsonWebKeyECPublic object
-   *
-   * @param jwk JsonWebKeyECPublic object
-   * @return Public key
-   */
-  PublicKeyPtr make_public_key(const JsonWebKeyECPublic& jwk);
+  using ECKeyPairPtr = std::shared_ptr<ECKeyPair>;
 
   /**
    * Create a new public / private ECDSA key pair on specified curve and
@@ -175,15 +150,16 @@ namespace ccf::crypto
    * @param curve_id Elliptic curve to use
    * @return Key pair
    */
-  KeyPairPtr make_key_pair(CurveID curve_id = service_identity_curve_choice);
+  ECKeyPairPtr make_ec_key_pair(
+    CurveID curve_id = service_identity_curve_choice);
 
   /**
    * Create a public / private ECDSA key pair from existing private key data
    *
    * @param pem PEM key to load
    * @return Key pair
    */
-  KeyPairPtr make_key_pair(const Pem& pem);
+  ECKeyPairPtr make_ec_key_pair(const Pem& pem);
 
   /**
    * Construct a new public / private ECDSA key pair from a JsonWebKeyECPrivate
@@ -192,5 +168,5 @@ namespace ccf::crypto
    * @param jwk JsonWebKeyECPrivate object
    * @return Key pair
    */
-  KeyPairPtr make_key_pair(const JsonWebKeyECPrivate& jwk);
+  ECKeyPairPtr make_ec_key_pair(const JsonWebKeyECPrivate& jwk);
 }

include/ccf/crypto/public_key.h renamed to include/ccf/crypto/ec_public_key.h

@@ -15,9 +15,11 @@
 
 namespace ccf::crypto
 {
-  class PublicKey
+  class ECPublicKey
   {
   public:
+    virtual ~ECPublicKey() = default;
+
     /**
      * Verify that a signature was produced on contents with the private key
      * associated with the public key held by the object.
@@ -151,7 +153,31 @@ namespace ccf::crypto
 
     [[nodiscard]] virtual JsonWebKeyECPublic public_key_jwk(
       const std::optional<std::string>& kid = std::nullopt) const = 0;
-
-    virtual ~PublicKey() = default;
   };
+
+  using ECPublicKeyPtr = std::shared_ptr<ECPublicKey>;
+
+  /**
+   * Construct ECPublicKey from a raw public key in PEM format
+   *
+   * @param pem Sequence of bytes containing the key in PEM format
+   * @return Public key
+   */
+  ECPublicKeyPtr make_ec_public_key(const Pem& pem);
+
+  /**
+   * Construct ECPublicKey from a raw public key in DER format
+   *
+   * @param der Sequence of bytes containing the key in DER format
+   * @return Public key
+   */
+  ECPublicKeyPtr make_ec_public_key(const std::vector<uint8_t>& der);
+
+  /**
+   * Construct ECPublicKey from a JsonWebKeyECPublic object
+   *
+   * @param jwk JsonWebKeyECPublic object
+   * @return Public key
+   */
+  ECPublicKeyPtr make_ec_public_key(const JsonWebKeyECPublic& jwk);
 }

include/ccf/crypto/eddsa_key_pair.h

@@ -5,9 +5,7 @@
 #include "ccf/crypto/curve.h"
 #include "ccf/crypto/eddsa_public_key.h"
 #include "ccf/crypto/jwk.h"
-#include "ccf/crypto/key_pair.h"
 #include "ccf/crypto/pem.h"
-#include "ccf/crypto/public_key.h"
 #include "ccf/crypto/san.h"
 
 #include <cstdint>

include/ccf/crypto/rsa_key_pair.h

@@ -3,7 +3,6 @@
 #pragma once
 
 #include "ccf/crypto/jwk.h"
-#include "ccf/crypto/key_pair.h"
 #include "ccf/crypto/pem.h"
 #include "ccf/crypto/rsa_public_key.h"
 
@@ -14,18 +13,18 @@
 
 namespace ccf::crypto
 {
-  class RSAKeyPair
+  class RSAKeyPair : public RSAPublicKey
   {
   public:
-    static constexpr size_t default_public_key_size = 2048;
-    static constexpr size_t default_public_exponent = 65537;
-
-    RSAKeyPair() = default;
-    RSAKeyPair(const RSAKeyPair&) = delete;
-    RSAKeyPair(const Pem& pem);
-    virtual ~RSAKeyPair() = default;
+    [[nodiscard]] virtual Pem private_key_pem() const = 0;
+    [[nodiscard]] virtual std::vector<uint8_t> private_key_der() const = 0;
+    [[nodiscard]] virtual JsonWebKeyRSAPrivate private_key_jwk(
+      const std::optional<std::string>& kid = std::nullopt) const = 0;
 
-    [[nodiscard]] virtual size_t key_size() const = 0;
+    [[nodiscard]] virtual std::vector<uint8_t> sign(
+      std::span<const uint8_t> d,
+      MDType md_type = MDType::NONE,
+      size_t salt_length = 0) const = 0;
 
     /**
      * Unwrap data using RSA-OAEP-256 (CKM_RSA_PKCS_OAEP)
@@ -35,71 +34,22 @@ namespace ccf::crypto
      *
      * @return Unwrapped data
      */
-    virtual std::vector<uint8_t> rsa_oaep_unwrap(
+    [[nodiscard]] virtual std::vector<uint8_t> rsa_oaep_unwrap(
       const std::vector<uint8_t>& input,
       const std::optional<std::vector<std::uint8_t>>& label = std::nullopt) = 0;
-
-    /**
-     * Get the private key in PEM format
-     */
-    [[nodiscard]] virtual Pem private_key_pem() const = 0;
-
-    /**
-     * Get the public key in PEM format
-     */
-    [[nodiscard]] virtual Pem public_key_pem() const = 0;
-
-    /**
-     * Get the public key in DER format
-     */
-    [[nodiscard]] virtual std::vector<uint8_t> public_key_der() const = 0;
-
-    [[nodiscard]] virtual std::vector<uint8_t> sign(
-      std::span<const uint8_t> d,
-      MDType md_type = MDType::NONE,
-      size_t salt_length = 0) const = 0;
-
-    virtual bool verify(
-      const uint8_t* contents,
-      size_t contents_size,
-      const uint8_t* signature,
-      size_t signature_size,
-      MDType md_type = MDType::NONE,
-      size_t salt_length = 0) = 0;
-
-    virtual bool verify(
-      const std::vector<uint8_t>& contents,
-      const std::vector<uint8_t>& signature,
-      MDType md_type = MDType::NONE,
-      size_t salt_length = 0)
-    {
-      return verify(
-        contents.data(),
-        contents.size(),
-        signature.data(),
-        signature.size(),
-        md_type,
-        salt_length);
-    }
-
-    [[nodiscard]] virtual JsonWebKeyRSAPrivate private_key_jwk_rsa(
-      const std::optional<std::string>& kid = std::nullopt) const = 0;
   };
 
-  using RSAPublicKeyPtr = std::shared_ptr<RSAPublicKey>;
   using RSAKeyPairPtr = std::shared_ptr<RSAKeyPair>;
 
-  RSAPublicKeyPtr make_rsa_public_key(const Pem& pem);
-  RSAPublicKeyPtr make_rsa_public_key(const std::vector<uint8_t>& der);
-  RSAPublicKeyPtr make_rsa_public_key(const JsonWebKeyRSAPublic& jwk);
-  RSAPublicKeyPtr make_rsa_public_key(const uint8_t* data, size_t size);
+  static constexpr size_t default_rsa_public_key_size = 2048;
+  static constexpr size_t default_rsa_public_exponent = 65537;
 
   /**
    * Create a new public / private RSA key pair with specified size and exponent
    */
   RSAKeyPairPtr make_rsa_key_pair(
-    size_t public_key_size = RSAKeyPair::default_public_key_size,
-    size_t public_exponent = RSAKeyPair::default_public_exponent);
+    size_t public_key_size = default_rsa_public_key_size,
+    size_t public_exponent = default_rsa_public_exponent);
 
   /**
    * Create a public / private RSA key pair from existing private key data