diff --git a/core/Cargo.toml b/core/Cargo.toml
index 8950e64..92d37ab 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -242,7 +242,7 @@ subtle = { version = "2.5", default-features = false, optional = true }  # Const
 tracing = { version = "0.1", optional = true }  # Structured spans / events for observability (Phase 4.5)
 
 # --- Crypto (std-only) ---
-x25519-dalek = { version = "2", optional = true, features = ["static_secrets", "zeroize"] }
+x25519-dalek = { version = "3", optional = true, features = ["static_secrets", "zeroize"] }
 ed25519-dalek = { version = "2", optional = true, features = ["zeroize", "rand_core"] }
 ring = { version = "0.17", optional = true }  # HW-accelerated AES-GCM (ARM64 AES intrinsics / x86 AES-NI) + ChaCha20-Poly1305
 # --- Header protection (QUIC RFC 9001 §5.4) primitives, T4.6 ---