feat: add test func for otp gen

test-utils/Cargo.toml

@@ -18,15 +18,21 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 rand_core = { version = "0.6.4", default-features = false }
+ark-ec = { version = "0.4", default-features = false }
 ark-serialize = { version = "0.4.0", default-features = false }
+ark-std = { version = "0.4", default-features = false }
 w3f-bls = { version = "0.1.3", default-features = false }
 murmur-core = { package = "murmur-core", path = "../core/", features = ["client"] }
+dleq_vrf = { git = "https://github.com/w3f/ring-vrf.git", default-features = false, features = ["getrandom"]}
 
 [features]
 default = ["std"]
 std = [
+    "ark-ec/std",
     "ark-serialize/std",
+    "ark-std/std",
     "w3f-bls/std",
     "murmur-core/std",
+    "dleq_vrf/std",
 ]
 no_std = []

test-utils/src/lib.rs

@@ -20,15 +20,35 @@
 
 use alloc::vec::Vec;
 use ark_serialize::CanonicalSerialize;
+use ark_std::rand::{CryptoRng, Rng};
 use rand_core::OsRng;
-use w3f_bls::{DoublePublicKey, DoublePublicKeyScheme, TinyBLS377};
+use ark_ec::CurveGroup;
+use w3f_bls::{DoublePublicKey, DoublePublicKeyScheme, EngineBLS, TinyBLS377};
+use dleq_vrf::SecretKey;
 
 extern crate alloc;
 
 pub use murmur_core::otp::BOTPGenerator;
+
 pub use murmur_core::murmur::MurmurStore;
+
 pub use murmur_core::murmur::generate_witness;
 
+pub fn otp<E: EngineBLS, R: Rng + CryptoRng + Sized>(
+	seed: Vec<u8>, 
+	when: u64, 
+	rng: &mut R
+) -> Vec<u8> {
+	let witness = generate_witness(seed.clone(), rng);
+	let secret_key = 
+		SecretKey::<<E::SignatureGroup as CurveGroup>::Affine>::from_seed(&witness);
+	let pubkey = secret_key.as_publickey();
+	let mut pubkey_bytes = Vec::new();
+	pubkey.serialize_compressed(&mut pubkey_bytes).unwrap();
+	let totp = BOTPGenerator::new(witness.to_vec()).unwrap();
+	totp.generate(when).as_bytes().to_vec()
+}
+
 pub fn get_dummy_beacon_pubkey() -> Vec<u8> {
 	let keypair = w3f_bls::KeypairVT::<TinyBLS377>::generate(&mut OsRng);
 	let double_public: DoublePublicKey<TinyBLS377> =