From dd8666efbcd5ad750b38d3563d54559f13c1b147 Mon Sep 17 00:00:00 2001
From: Sarthak Shubham <sarthakshubham23@gmail.com>
Date: Sun, 27 Sep 2026 12:18:43 +0530
Subject: [PATCH] Fix #826: Suppress cryptography FFDH deprecation warning and
 add decrepit fallback

---
 asyncssh/crypto/dh.py | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/asyncssh/crypto/dh.py b/asyncssh/crypto/dh.py
index 52e09e7e..554f0b2a 100644
--- a/asyncssh/crypto/dh.py
+++ b/asyncssh/crypto/dh.py
@@ -20,27 +20,42 @@
 
 """A shim around PyCA for Diffie Hellman key exchange"""
 
-from cryptography.hazmat.primitives.asymmetric import dh
+import warnings
+from cryptography.utils import CryptographyDeprecationWarning
+
+try:
+    from cryptography.hazmat.primitives.asymmetric import dh
+except ImportError:
+    from cryptography.hazmat.decrepit.asymmetric import dh
 
 
 class DH:
     """A shim around PyCA for Diffie Hellman key exchange"""
 
     def __init__(self, g: int, p: int):
-        self._pn = dh.DHParameterNumbers(p, g)
-        self._priv_key = self._pn.parameters().generate_private_key()
+        with warnings.catch_warnings():
+            warnings.simplefilter('ignore', CryptographyDeprecationWarning)
+
+            self._pn = dh.DHParameterNumbers(p, g)
+            self._priv_key = self._pn.parameters().generate_private_key()
 
     def get_public(self) -> int:
         """Return the public key to send in the handshake"""
 
-        pub_key = self._priv_key.public_key()
+        with warnings.catch_warnings():
+            warnings.simplefilter('ignore', CryptographyDeprecationWarning)
+            
+            pub_key = self._priv_key.public_key()
 
-        return pub_key.public_numbers().y
+            return pub_key.public_numbers().y
 
     def get_shared(self, peer_public: int) -> int:
         """Return the shared key from the peer's public key"""
 
-        peer_key = dh.DHPublicNumbers(peer_public, self._pn).public_key()
-        shared_key = self._priv_key.exchange(peer_key)
+        with warnings.catch_warnings():
+            warnings.simplefilter('ignore', CryptographyDeprecationWarning)
+
+            peer_key = dh.DHPublicNumbers(peer_public, self._pn).public_key()
+            shared_key = self._priv_key.exchange(peer_key)
 
         return int.from_bytes(shared_key, 'big')