diff --git a/sdk/examples/remote-signer/app/signer.py b/sdk/examples/remote-signer/app/signer.py
index 8ec7a68..fd31d3a 100644
--- a/sdk/examples/remote-signer/app/signer.py
+++ b/sdk/examples/remote-signer/app/signer.py
@@ -1,6 +1,11 @@
 import hashlib
-import ecdsa
-from ecdsa import SECP256k1
+
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric import ec
+from cryptography.hazmat.primitives.asymmetric.utils import (
+    Prehashed,
+    decode_dss_signature,
+)
 
 # secp256k1 curve order half (for low-S check)
 _HALF_ORDER = 0x3FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DBFE92F1A9F2A0746
@@ -29,14 +34,17 @@ def _bitcoin_message_magic(message: bytes) -> bytes:
 
 def sign_bytes(message: bytes, private_key_bytes: bytes) -> str:
     """Sign message bytes using the Bitcoin signed message format."""
-    privkey = ecdsa.SigningKey.from_string(private_key_bytes, curve=SECP256k1)
+    privkey = ec.derive_private_key(
+        int.from_bytes(private_key_bytes, "big"), ec.SECP256K1()
+    )
 
     prefixed = _bitcoin_message_magic(message)
     digest = hashlib.sha256(hashlib.sha256(prefixed).digest()).digest()
-    raw = privkey.sign_digest(digest, sigencode=ecdsa.util.sigencode_string)
+    der_sig = privkey.sign(digest, ec.ECDSA(Prehashed(hashes.SHA256())))
+    r, s = decode_dss_signature(der_sig)
+    raw = r.to_bytes(32, "big") + s.to_bytes(32, "big")
 
-    s_int = int.from_bytes(raw[32:], "big")
-    rec_id = 27 if s_int <= _HALF_ORDER else 28
+    rec_id = 27 if s <= _HALF_ORDER else 28
 
     return bytes([rec_id]).hex() + raw.hex()
 
diff --git a/sdk/examples/remote-signer/requirements.txt b/sdk/examples/remote-signer/requirements.txt
index f8f8cd1..8c1005e 100644
--- a/sdk/examples/remote-signer/requirements.txt
+++ b/sdk/examples/remote-signer/requirements.txt
@@ -1,7 +1,7 @@
 fastapi==0.115.6
 uvicorn==0.34.0
-ecdsa==0.19.1
-python-dotenv==1.0.1
-pytest==8.3.4
-pytest-asyncio==0.25.2
+cryptography==44.0.0
+python-dotenv==1.2.2
+pytest==9.0.3
+pytest-asyncio==1.4.0
 httpx==0.28.1