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diff --git a/vendor/signature/src/hazmat.rs b/vendor/signature/src/hazmat.rs
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+++ b/vendor/signature/src/hazmat.rs
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+//! Hazardous Materials: low-level APIs which can be insecure if misused.
+//!
+//! The traits in this module are not generally recommended, and should only be
+//! used in special cases where they are specifically needed.
+//!
+//! Using them incorrectly can introduce security vulnerabilities. Please
+//! carefully read the documentation before attempting to use them.
+
+use crate::Error;
+
+#[cfg(feature = "rand_core")]
+use crate::rand_core::CryptoRngCore;
+
+/// Sign the provided message prehash, returning a digital signature.
+pub trait PrehashSigner<S> {
+    /// Attempt to sign the given message digest, returning a digital signature
+    /// on success, or an error if something went wrong.
+    ///
+    /// The `prehash` parameter should be the output of a secure cryptographic
+    /// hash function.
+    ///
+    /// This API takes a `prehash` byte slice as there can potentially be many
+    /// compatible lengths for the message digest for a given concrete signature
+    /// algorithm.
+    ///
+    /// Allowed lengths are algorithm-dependent and up to a particular
+    /// implementation to decide.
+    fn sign_prehash(&self, prehash: &[u8]) -> Result<S, Error>;
+}
+
+/// Sign the provided message prehash using the provided external randomness source, returning a digital signature.
+#[cfg(feature = "rand_core")]
+pub trait RandomizedPrehashSigner<S> {
+    /// Attempt to sign the given message digest, returning a digital signature
+    /// on success, or an error if something went wrong.
+    ///
+    /// The `prehash` parameter should be the output of a secure cryptographic
+    /// hash function.
+    ///
+    /// This API takes a `prehash` byte slice as there can potentially be many
+    /// compatible lengths for the message digest for a given concrete signature
+    /// algorithm.
+    ///
+    /// Allowed lengths are algorithm-dependent and up to a particular
+    /// implementation to decide.
+    fn sign_prehash_with_rng(
+        &self,
+        rng: &mut impl CryptoRngCore,
+        prehash: &[u8],
+    ) -> Result<S, Error>;
+}
+
+/// Verify the provided message prehash using `Self` (e.g. a public key)
+pub trait PrehashVerifier<S> {
+    /// Use `Self` to verify that the provided signature for a given message
+    /// `prehash` is authentic.
+    ///
+    /// The `prehash` parameter should be the output of a secure cryptographic
+    /// hash function.
+    ///
+    /// Returns `Error` if it is inauthentic or some other error occurred, or
+    /// otherwise returns `Ok(())`.
+    ///
+    /// # ⚠️ Security Warning
+    ///
+    /// If `prehash` is something other than the output of a cryptographically
+    /// secure hash function, an attacker can potentially forge signatures by
+    /// solving a system of linear equations.
+    fn verify_prehash(&self, prehash: &[u8], signature: &S) -> Result<(), Error>;
+}