Update argon2 to v0.5 (#314)

Cargo.toml

@@ -21,7 +21,7 @@ serde = ["dep:serde", "generic-array/serde", "voprf/serde"]
 std = ["dep:getrandom"]
 
 [dependencies]
-argon2 = { version = "0.4", default-features = false, features = [
+argon2 = { version = "0.5", default-features = false, features = [
   "alloc",
 ], optional = true }
 curve25519-dalek = { version = "=4.0.0-rc.1", default-features = false, features = [

src/ksf.rs

@@ -11,10 +11,6 @@ use generic_array::{ArrayLength, GenericArray};
 
 use crate::errors::InternalError;
 
-/// Recommended salt length for argon2-based password hashing.
-#[cfg(feature = "argon2")]
-const ARGON2_RECOMMENDED_SALT_LEN: usize = 16;
-
 /// Used for the key stretching function in OPAQUE
 pub trait Ksf: Default {
     /// Computes the key stretching function
@@ -44,7 +40,7 @@ impl Ksf for argon2::Argon2<'_> {
         input: GenericArray<u8, L>,
     ) -> Result<GenericArray<u8, L>, InternalError> {
         let mut output = GenericArray::default();
-        self.hash_password_into(&input, &[0; ARGON2_RECOMMENDED_SALT_LEN], &mut output)
+        self.hash_password_into(&input, &[0; argon2::RECOMMENDED_SALT_LEN], &mut output)
             .map_err(|_| InternalError::KsfError)?;
         Ok(output)
     }