remove dependency on rand

Cargo.toml

@@ -17,7 +17,7 @@ edition = "2018"
 # and -accelerated suffix means that this resolver will be the default used by the Builder.
 [features]
 default = ["default-resolver"]
-default-resolver = ["aes-gcm", "chacha20poly1305", "blake2", "sha2", "x25519-dalek", "rand"]
+default-resolver = ["aes-gcm", "chacha20poly1305", "blake2", "sha2", "x25519-dalek"]
 nightly = ["blake2/simd_opt", "x25519-dalek/nightly", "subtle/nightly"]
 ring-resolver = ["ring"]
 ring-accelerated = ["ring-resolver", "default-resolver"]
@@ -37,14 +37,13 @@ harness = false
 travis-ci = { repository = "mcginty/snow", branch = "master" }
 
 [dependencies]
-rand_core = "0.6"
+rand_core = { version = "0.6", features = ["std", "getrandom"] }
 subtle = "2.4"
 
 # default crypto provider
 aes-gcm = { version = "0.9", optional = true }
 chacha20poly1305 = { version = "0.9", optional = true }
 blake2 = { version = "0.10", optional = true }
-rand = { version = "0.8", optional = true }
 sha2 = { version = "0.10", optional = true }
 x25519-dalek = { version = "1.1", optional = true }
 pqcrypto-kyber = { version = "0.7", optional = true }

src/resolvers/default.rs

@@ -10,7 +10,7 @@ use core::convert::TryInto;
 use pqcrypto_kyber::kyber1024;
 #[cfg(feature = "pqclean_kyber1024")]
 use pqcrypto_traits::kem::{Ciphertext, PublicKey, SecretKey, SharedSecret};
-use rand::rngs::OsRng;
+use rand_core::OsRng;
 use sha2::{Digest, Sha256, Sha512};
 use x25519_dalek as x25519;