feat: make the implementation generic around the PublicKey/PrivateKey

README.md

@@ -12,7 +12,7 @@ A portable RSA implementation in pure Rust.
 ## Example
 
 ```rust
-use rsa::{Pkcs1v15Encrypt, PublicKey, RsaPrivateKey, RsaPublicKey};
+use rsa::{Pkcs1v15Encrypt, PublicKey, PrivateKey, RsaPrivateKey, RsaPublicKey};
 
 let mut rng = rand::thread_rng();
 let bits = 2048;

src/key.rs

@@ -31,7 +31,17 @@ pub trait PublicKeyParts {
     }
 }
 
-pub trait PrivateKey: DecryptionPrimitive + PublicKeyParts {}
+/// Generic trait for operations on a private key.
+pub trait PrivateKey: DecryptionPrimitive + PublicKeyParts + Sized {
+    /// Corresponding public key type
+    type PublicKey: PublicKey;
+
+    /// generate new random private key of the specified bit size
+    fn new<R: CryptoRngCore + ?Sized>(rng: &mut R, bit_size: usize) -> Result<Self>;
+
+    /// convert this private key to the corresponding public key
+    fn to_public_key(&self) -> Self::PublicKey;
+}
 
 /// Represents the public part of an RSA key.
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
@@ -251,14 +261,24 @@ impl PublicKeyParts for RsaPrivateKey {
     }
 }
 
-impl PrivateKey for RsaPrivateKey {}
+impl PrivateKey for RsaPrivateKey {
+    type PublicKey = RsaPublicKey;
 
-impl RsaPrivateKey {
     /// Generate a new Rsa key pair of the given bit size using the passed in `rng`.
-    pub fn new<R: CryptoRngCore + ?Sized>(rng: &mut R, bit_size: usize) -> Result<RsaPrivateKey> {
+    fn new<R: CryptoRngCore + ?Sized>(rng: &mut R, bit_size: usize) -> Result<RsaPrivateKey> {
         generate_multi_prime_key(rng, 2, bit_size)
     }
 
+    /// Get the public key from the private key, cloning `n` and `e`.
+    ///
+    /// Generally this is not needed since `RsaPrivateKey` implements the `PublicKey` trait,
+    /// but it can occasionally be useful to discard the private information entirely.
+    fn to_public_key(&self) -> Self::PublicKey {
+        self.pubkey_components.clone()
+    }
+}
+
+impl RsaPrivateKey {
     /// Generate a new RSA key pair of the given bit size and the public exponent
     /// using the passed in `rng`.
     ///
@@ -297,14 +317,6 @@ impl RsaPrivateKey {
         Ok(k)
     }
 
-    /// Get the public key from the private key, cloning `n` and `e`.
-    ///
-    /// Generally this is not needed since `RsaPrivateKey` implements the `PublicKey` trait,
-    /// but it can occasionally be useful to discard the private information entirely.
-    pub fn to_public_key(&self) -> RsaPublicKey {
-        self.pubkey_components.clone()
-    }
-
     /// Performs some calculations to speed up private key operations.
     pub fn precompute(&mut self) -> Result<()> {
         if self.precomputed.is_some() {

src/lib.rs

@@ -14,7 +14,7 @@
 //!
 //! ## PKCS#1 v1.5 encryption
 //! ```
-//! use rsa::{PublicKey, RsaPrivateKey, RsaPublicKey, Pkcs1v15Encrypt};
+//! use rsa::{PrivateKey, PublicKey, RsaPrivateKey, RsaPublicKey, Pkcs1v15Encrypt};
 //!
 //! let mut rng = rand::thread_rng();
 //!
@@ -34,7 +34,7 @@
 //!
 //! ## OAEP encryption
 //! ```
-//! use rsa::{PublicKey, RsaPrivateKey, RsaPublicKey, Oaep};
+//! use rsa::{PrivateKey, PublicKey, RsaPrivateKey, RsaPublicKey, Oaep};
 //!
 //! let mut rng = rand::thread_rng();
 //!
@@ -60,7 +60,7 @@
 //!
 #![cfg_attr(feature = "sha2", doc = "```")]
 #![cfg_attr(not(feature = "sha2"), doc = "```ignore")]
-//! use rsa::RsaPrivateKey;
+//! use rsa::{PrivateKey, RsaPrivateKey};
 //! use rsa::pkcs1v15::{SigningKey, VerifyingKey};
 //! use rsa::signature::{Keypair, RandomizedSigner, SignatureEncoding, Verifier};
 //! use rsa::sha2::{Digest, Sha256};
@@ -87,7 +87,7 @@
 //!
 #![cfg_attr(feature = "sha2", doc = "```")]
 #![cfg_attr(not(feature = "sha2"), doc = "```ignore")]
-//! use rsa::RsaPrivateKey;
+//! use rsa::{PrivateKey, RsaPrivateKey};
 //! use rsa::pss::{BlindedSigningKey, VerifyingKey};
 //! use rsa::signature::{Keypair,RandomizedSigner, SignatureEncoding, Verifier};
 //! use rsa::sha2::{Digest, Sha256};
@@ -96,7 +96,7 @@
 //!
 //! let bits = 2048;
 //! let private_key = RsaPrivateKey::new(&mut rng, bits).expect("failed to generate a key");
-//! let signing_key = BlindedSigningKey::<Sha256>::new(private_key);
+//! let signing_key = BlindedSigningKey::<Sha256, _>::new(private_key);
 //! let verifying_key = signing_key.verifying_key();
 //!
 //! // Sign
@@ -241,7 +241,7 @@ pub use pkcs8;
 pub use sha2;
 
 pub use crate::{
-    key::{PublicKey, PublicKeyParts, RsaPrivateKey, RsaPublicKey},
+    key::{PrivateKey, PublicKey, PublicKeyParts, RsaPrivateKey, RsaPublicKey},
     oaep::Oaep,
     padding::{PaddingScheme, SignatureScheme},
     pkcs1v15::{Pkcs1v15Encrypt, Pkcs1v15Sign},