Adds support for the SignatureBitStringEncoding trait (#328)

Cargo.lock

@@ -536,6 +536,7 @@ dependencies = [
  "sha2",
  "sha3",
  "signature",
+ "spki",
  "subtle",
  "zeroize",
 ]
@@ -671,9 +672,9 @@ checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
 
 [[package]]
 name = "spki"
-version = "0.7.1"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37a5be806ab6f127c3da44b7378837ebf01dadca8510a0e572460216b228bd0e"
+checksum = "9d1e996ef02c474957d681f1b05213dfb0abab947b446a62d37770b23500184a"
 dependencies = [
  "base64ct",
  "der",

Cargo.toml

@@ -24,7 +24,8 @@ subtle = { version = "2.1.1", default-features = false }
 digest = { version = "0.10.5", default-features = false, features = ["alloc", "oid"] }
 pkcs1 = { version = "0.7.5", default-features = false, features = ["alloc", "pkcs8"] }
 pkcs8 = { version = "0.10.2", default-features = false, features = ["alloc"] }
-signature = { version = "2", default-features = false , features = ["digest", "rand_core"] }
+signature = { version = "2", default-features = false , features = ["alloc", "digest", "rand_core"] }
+spki = { version = "0.7.2", default-features = false, features = ["alloc"] }
 zeroize = { version = "1.5", features = ["alloc"] }
 
 # optional dependencies

src/pkcs1v15/signature.rs

@@ -3,6 +3,10 @@ pub use ::signature::{
     DigestSigner, DigestVerifier, Error, Keypair, RandomizedDigestSigner, RandomizedSigner, Result,
     SignatureEncoding, Signer, Verifier,
 };
+use spki::{
+    der::{asn1::BitString, Result as DerResult},
+    SignatureBitStringEncoding,
+};
 
 use crate::algorithms::pad::uint_to_be_pad;
 use alloc::{boxed::Box, string::ToString};
@@ -22,6 +26,12 @@ impl SignatureEncoding for Signature {
     type Repr = Box<[u8]>;
 }
 
+impl SignatureBitStringEncoding for Signature {
+    fn to_bitstring(&self) -> DerResult<BitString> {
+        BitString::new(0, self.to_vec())
+    }
+}
+
 impl TryFrom<&[u8]> for Signature {
     type Error = signature::Error;
 

src/pss/signature.rs

@@ -3,6 +3,10 @@ pub use ::signature::{
     DigestSigner, DigestVerifier, Error, Keypair, RandomizedDigestSigner, RandomizedSigner, Result,
     SignatureEncoding, Signer, Verifier,
 };
+use spki::{
+    der::{asn1::BitString, Result as DerResult},
+    SignatureBitStringEncoding,
+};
 
 use crate::algorithms::pad::uint_to_be_pad;
 use alloc::{boxed::Box, string::ToString};
@@ -22,6 +26,12 @@ impl SignatureEncoding for Signature {
     type Repr = Box<[u8]>;
 }
 
+impl SignatureBitStringEncoding for Signature {
+    fn to_bitstring(&self) -> DerResult<BitString> {
+        BitString::new(0, self.to_vec())
+    }
+}
+
 impl TryFrom<&[u8]> for Signature {
     type Error = signature::Error;