pkcs8: replace from_pkcs8_private_key_info with TryFrom

pkcs1/src/pkcs8.rs

@@ -27,7 +27,7 @@ impl<T: DecodePrivateKey> DecodeRsaPrivateKey for T {
             parameters: Some(Null.into()),
         };
 
-        Ok(Self::from_pkcs8_private_key_info(PrivateKeyInfo {
+        Ok(Self::try_from(PrivateKeyInfo {
             algorithm,
             private_key,
             public_key: None,

pkcs8/src/document/private_key.rs

@@ -84,10 +84,6 @@ impl PrivateKeyDocument {
 }
 
 impl DecodePrivateKey for PrivateKeyDocument {
-    fn from_pkcs8_private_key_info(private_key: PrivateKeyInfo<'_>) -> Result<Self> {
-        Ok(Self::from_msg(&private_key)?)
-    }
-
     fn from_pkcs8_der(bytes: &[u8]) -> Result<Self> {
         Ok(Self::from_der(bytes)?)
     }
@@ -147,15 +143,15 @@ impl TryFrom<PrivateKeyInfo<'_>> for PrivateKeyDocument {
     type Error = Error;
 
     fn try_from(private_key_info: PrivateKeyInfo<'_>) -> Result<PrivateKeyDocument> {
-        PrivateKeyDocument::from_pkcs8_private_key_info(private_key_info)
+        Self::try_from(&private_key_info)
     }
 }
 
 impl TryFrom<&PrivateKeyInfo<'_>> for PrivateKeyDocument {
     type Error = Error;
 
     fn try_from(private_key_info: &PrivateKeyInfo<'_>) -> Result<PrivateKeyDocument> {
-        PrivateKeyDocument::from_pkcs8_private_key_info(private_key_info.clone())
+        Ok(Self::from_msg(private_key_info)?)
     }
 }
 

pkcs8/src/traits.rs

@@ -1,6 +1,6 @@
 //! Traits for parsing objects from PKCS#8 encoded documents
 
-use crate::{PrivateKeyInfo, Result};
+use crate::{Error, PrivateKeyInfo, Result};
 
 #[cfg(feature = "alloc")]
 use {crate::PrivateKeyDocument, der::Document};
@@ -17,14 +17,11 @@ use std::path::Path;
 use {crate::LineEnding, alloc::string::String, zeroize::Zeroizing};
 
 /// Parse a private key object from a PKCS#8 encoded document.
-pub trait DecodePrivateKey: Sized {
-    /// Parse the [`PrivateKeyInfo`] from a PKCS#8-encoded document.
-    fn from_pkcs8_private_key_info(private_key_info: PrivateKeyInfo<'_>) -> Result<Self>;
-
+pub trait DecodePrivateKey: for<'a> TryFrom<PrivateKeyInfo<'a>, Error = Error> + Sized {
     /// Deserialize PKCS#8 private key from ASN.1 DER-encoded data
     /// (binary format).
     fn from_pkcs8_der(bytes: &[u8]) -> Result<Self> {
-        Self::from_pkcs8_private_key_info(PrivateKeyInfo::try_from(bytes)?)
+        Self::try_from(PrivateKeyInfo::try_from(bytes)?)
     }
 
     /// Deserialize encrypted PKCS#8 private key from ASN.1 DER-encoded data
@@ -41,7 +38,7 @@ pub trait DecodePrivateKey: Sized {
     #[cfg(feature = "alloc")]
     #[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
     fn from_pkcs8_doc(doc: &PrivateKeyDocument) -> Result<Self> {
-        Self::from_pkcs8_private_key_info(doc.decode())
+        Self::try_from(doc.decode())
     }
 
     /// Deserialize PKCS#8-encoded private key from PEM.

sec1/src/pkcs8.rs

@@ -28,7 +28,7 @@ impl<T: DecodePrivateKey> DecodeEcPrivateKey for T {
             parameters: params_oid.as_ref().map(Into::into),
         };
 
-        Ok(Self::from_pkcs8_private_key_info(PrivateKeyInfo {
+        Ok(Self::try_from(PrivateKeyInfo {
             algorithm,
             private_key,
             public_key: None,