Convert signature to ecdsa::Signature

Signed-off-by: Arthur Gautier <[email protected]>

Author: baloo

tss-esapi/src/abstraction/mod.rs

@@ -10,6 +10,7 @@ pub mod public;
 pub mod transient;
 
 mod hashing;
+mod signatures;
 pub use hashing::AssociatedHashingAlgorithm;
 
 use std::convert::TryFrom;

tss-esapi/src/abstraction/signatures.rs

@@ -0,0 +1,42 @@
+// Copyright 2024 Contributors to the Parsec project.
+// SPDX-License-Identifier: Apache-2.0
+
+use crate::{structures::EccSignature, Error, Result, WrapperErrorKind};
+
+use std::convert::TryFrom;
+
+use ecdsa::SignatureSize;
+use elliptic_curve::{
+    generic_array::{typenum::Unsigned, ArrayLength},
+    FieldBytes, FieldBytesSize, PrimeCurve,
+};
+
+impl<C> TryFrom<EccSignature> for ecdsa::Signature<C>
+where
+    C: PrimeCurve,
+    SignatureSize<C>: ArrayLength<u8>,
+{
+    type Error = Error;
+
+    fn try_from(signature: EccSignature) -> Result<Self> {
+        let r = signature.signature_r().as_slice();
+        let s = signature.signature_s().as_slice();
+
+        if r.len() != FieldBytesSize::<C>::USIZE {
+            return Err(Error::local_error(WrapperErrorKind::InvalidParam));
+        }
+        if s.len() != FieldBytesSize::<C>::USIZE {
+            return Err(Error::local_error(WrapperErrorKind::InvalidParam));
+        }
+
+        let signature = ecdsa::Signature::from_scalars(
+            FieldBytes::<C>::from_slice(r).clone(),
+            FieldBytes::<C>::from_slice(s).clone(),
+        )
+        .map_err(|_| Error::local_error(WrapperErrorKind::InvalidParam))?;
+        Ok(signature)
+    }
+}
+
+// TODO(baloo): impl TryFrom<RsaSignature> for rsa::pkcs1v15::Signature
+// TODO(baloo): impl TryFrom<RsaSignature> for rsa::pss::Signature