Implement MultipartSign/Verify (#525)

Implementation of `MultipartSigner` and `MultipartVerifier` added in
RustCrypto/traits#1880.

Author: daxpedda

Cargo.lock

@@ -19,7 +19,7 @@ subtle = { version = "2.6.1", default-features = false }
 digest = { version = "0.11.0-rc.0", default-features = false, features = ["alloc", "oid"] }
 pkcs1 = { version = "0.8.0-rc.2", default-features = false, features = ["alloc", "pkcs8"] }
 pkcs8 = { version = "0.11.0-rc.4", default-features = false, features = ["alloc"] }
-signature = { version = "3.0.0-rc.0", default-features = false, features = ["alloc", "digest", "rand_core"] }
+signature = { version = "3.0.0-rc.1", default-features = false, features = ["alloc", "digest", "rand_core"] }
 spki = { version = "0.8.0-rc.2", default-features = false, features = ["alloc"] }
 zeroize = { version = "1.5", features = ["alloc"] }
 crypto-bigint = { version = "0.7.0-pre.4", default-features = false, features = ["zeroize", "alloc"] }

Cargo.toml

@@ -18,7 +18,8 @@ use {
 };
 
 use signature::{
-    hazmat::PrehashSigner, DigestSigner, Keypair, RandomizedDigestSigner, RandomizedSigner, Signer,
+    hazmat::PrehashSigner, DigestSigner, Keypair, MultipartSigner, RandomizedDigestSigner,
+    RandomizedMultipartSigner, RandomizedSigner, Signer,
 };
 use zeroize::ZeroizeOnDrop;
 
@@ -135,7 +136,22 @@ where
         rng: &mut R,
         msg: &[u8],
     ) -> signature::Result<Signature> {
-        sign(Some(rng), &self.inner, &self.prefix, &D::digest(msg))?
+        self.try_multipart_sign_with_rng(rng, &[msg])
+    }
+}
+
+impl<D> RandomizedMultipartSigner<Signature> for SigningKey<D>
+where
+    D: Digest,
+{
+    fn try_multipart_sign_with_rng<R: TryCryptoRng + ?Sized>(
+        &self,
+        rng: &mut R,
+        msg: &[&[u8]],
+    ) -> signature::Result<Signature> {
+        let mut digest = D::new();
+        msg.iter().for_each(|slice| digest.update(slice));
+        sign(Some(rng), &self.inner, &self.prefix, &digest.finalize())?
             .as_slice()
             .try_into()
     }
@@ -146,7 +162,18 @@ where
     D: Digest,
 {
     fn try_sign(&self, msg: &[u8]) -> signature::Result<Signature> {
-        sign::<DummyRng>(None, &self.inner, &self.prefix, &D::digest(msg))?
+        self.try_multipart_sign(&[msg])
+    }
+}
+
+impl<D> MultipartSigner<Signature> for SigningKey<D>
+where
+    D: Digest,
+{
+    fn try_multipart_sign(&self, msg: &[&[u8]]) -> signature::Result<Signature> {
+        let mut digest = D::new();
+        msg.iter().for_each(|slice| digest.update(slice));
+        sign::<DummyRng>(None, &self.inner, &self.prefix, &digest.finalize())?
             .as_slice()
             .try_into()
     }

src/pkcs1v15/signing_key.rs

@@ -12,7 +12,8 @@ use pkcs8::{
 };
 use rand_core::{CryptoRng, TryCryptoRng};
 use signature::{
-    hazmat::RandomizedPrehashSigner, Keypair, RandomizedDigestSigner, RandomizedSigner,
+    hazmat::RandomizedPrehashSigner, Keypair, RandomizedDigestSigner, RandomizedMultipartSigner,
+    RandomizedSigner,
 };
 use zeroize::ZeroizeOnDrop;
 #[cfg(feature = "serde")]
@@ -93,7 +94,23 @@ where
         rng: &mut R,
         msg: &[u8],
     ) -> signature::Result<Signature> {
-        sign_digest::<_, D>(rng, true, &self.inner, &D::digest(msg), self.salt_len)?
+        self.try_multipart_sign_with_rng(rng, &[msg])
+    }
+}
+
+impl<D> RandomizedMultipartSigner<Signature> for BlindedSigningKey<D>
+where
+    D: Digest + FixedOutputReset,
+{
+    fn try_multipart_sign_with_rng<R: TryCryptoRng + ?Sized>(
+        &self,
+        rng: &mut R,
+        msg: &[&[u8]],
+    ) -> signature::Result<Signature> {
+        let mut digest = D::new();
+        msg.iter()
+            .for_each(|slice| <D as Digest>::update(&mut digest, slice));
+        sign_digest::<_, D>(rng, true, &self.inner, &digest.finalize(), self.salt_len)?
             .as_slice()
             .try_into()
     }

src/pss/blinded_signing_key.rs

@@ -13,7 +13,8 @@ use pkcs8::{
 };
 use rand_core::{CryptoRng, TryCryptoRng};
 use signature::{
-    hazmat::RandomizedPrehashSigner, Keypair, RandomizedDigestSigner, RandomizedSigner,
+    hazmat::RandomizedPrehashSigner, Keypair, RandomizedDigestSigner, RandomizedMultipartSigner,
+    RandomizedSigner,
 };
 use zeroize::ZeroizeOnDrop;
 #[cfg(feature = "serde")]
@@ -25,7 +26,7 @@ use {
 #[cfg(feature = "os_rng")]
 use {
     rand_core::OsRng,
-    signature::{hazmat::PrehashSigner, Signer},
+    signature::{hazmat::PrehashSigner, MultipartSigner, Signer},
 };
 
 /// Signing key for producing RSASSA-PSS signatures as described in
@@ -118,6 +119,22 @@ where
     }
 }
 
+impl<D> RandomizedMultipartSigner<Signature> for SigningKey<D>
+where
+    D: Digest + FixedOutputReset,
+{
+    fn try_multipart_sign_with_rng<R: TryCryptoRng + ?Sized>(
+        &self,
+        rng: &mut R,
+        msg: &[&[u8]],
+    ) -> signature::Result<Signature> {
+        let mut digest = D::new();
+        msg.iter()
+            .for_each(|slice| <D as Digest>::update(&mut digest, slice));
+        self.try_sign_digest_with_rng(rng, digest)
+    }
+}
+
 impl<D> RandomizedPrehashSigner<Signature> for SigningKey<D>
 where
     D: Digest + FixedOutputReset,
@@ -153,6 +170,16 @@ where
     }
 }
 
+#[cfg(feature = "os_rng")]
+impl<D> MultipartSigner<Signature> for SigningKey<D>
+where
+    D: Digest + FixedOutputReset,
+{
+    fn try_multipart_sign(&self, msg: &[&[u8]]) -> signature::Result<Signature> {
+        self.try_multipart_sign_with_rng(&mut OsRng, msg)
+    }
+}
+
 //
 // Other trait impls
 //