diff --git a/Cargo.lock b/Cargo.lock
index 96435ee..0e17004 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -379,9 +379,9 @@ dependencies = [
 
 [[package]]
 name = "num-bigint"
-version = "0.4.8"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c89e69e7e0f03bea5ef08013795c25018e101932225a656383bd384495ecc367"
+checksum = "93e7820bc0a80a0238e650327316f929ba18d5be054b647490a3a6a339f3e7c0"
 dependencies = [
  "num-integer",
  "num-traits",
diff --git a/spake2/Cargo.toml b/spake2/Cargo.toml
index 4e89620..655ec3d 100644
--- a/spake2/Cargo.toml
+++ b/spake2/Cargo.toml
@@ -26,7 +26,7 @@ getrandom = { version = "0.4", optional = true, features = ["sys_rng"] }
 [dev-dependencies]
 bencher = "0.1"
 hex = "0.4"
-num-bigint = "0.4"
+num-bigint = "0.5"
 
 [features]
 default = []