Cargo.toml: update to latest hkdf

2 files changed, 2 insertions, 2 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 128a787..404bc0c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,7 +19,7 @@ travis-ci = { repository = "warner/spake2.rs" }
 curve25519-dalek = "0.17"
 rand = "0.5"
 sha2 = "0.7"
-hkdf = "0.4"
+hkdf = "0.5"
 num-bigint = "0.1"
 hex = "0.3"
 
diff --git a/src/spake2.rs b/src/spake2.rs
index 7a32f5a..7f26958 100644
--- a/src/spake2.rs
+++ b/src/spake2.rs
@@ -145,7 +145,7 @@ fn ed25519_hash_to_scalar(s: &[u8]) -> c2_Scalar {
     //  i = int(h, 16)
     //  i % q
 
-    let okm = Hkdf::<Sha256>::extract(b"", s).expand(b"SPAKE2 pw", 32 + 16);
+    let okm = Hkdf::<Sha256>::extract(Some(b""), s).expand(b"SPAKE2 pw", 32 + 16);
     //println!("expanded:   {}{}", "................................", okm.iter().to_hex()); // ok
 
     let mut reducible = [0u8; 64]; // little-endian