diff --git a/Cargo.toml b/Cargo.toml
index 7dc63a7..4f46a48 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,6 +29,10 @@ features = ["i128_support"]
 default-features = false
 optional = true
 
+[dependencies.rand_os]
+version = "0.1"
+optional = true
+
 [dependencies.serde]
 version = "^1.0"
 optional = true
@@ -48,8 +52,7 @@ version = "0.2"
 hex = "^0.3"
 bincode = "^0.9"
 criterion = "0.2"
-rand_os = "0.1.0"
-rand_chacha = "0.1.0"
+rand_os = "0.1"
 
 [[bench]]
 name = "ed25519_benchmarks"
@@ -57,9 +60,10 @@ harness = false
 
 [features]
 default = ["std", "u64_backend"]
-std = ["curve25519-dalek/std", "rand", "sha2/std"]
-alloc = ["curve25519-dalek/alloc"]
+std = ["curve25519-dalek/std", "rand_os", "sha2/std"]
+alloc = ["curve25519-dalek/alloc", "rand_os"]
 nightly = ["curve25519-dalek/nightly", "clear_on_drop/nightly"]
+batch = ["rand"]
 asm = ["sha2/asm"]
 yolocrypto = ["curve25519-dalek/yolocrypto"]
 u64_backend = ["curve25519-dalek/u64_backend"]
diff --git a/src/ed25519.rs b/src/ed25519.rs
index f483bd1..1b6334a 100644
--- a/src/ed25519.rs
+++ b/src/ed25519.rs
@@ -28,11 +28,11 @@ pub use sha2::Sha512;
 use curve25519_dalek::digest::generic_array::typenum::U64;
 pub use curve25519_dalek::digest::Digest;
 
-#[cfg(any(feature = "alloc", feature = "std"))]
+#[cfg(all(feature = "batch", any(feature = "alloc", feature = "std")))]
 use curve25519_dalek::constants;
-#[cfg(any(feature = "alloc", feature = "std"))]
+#[cfg(all(feature = "batch", any(feature = "alloc", feature = "std")))]
 use curve25519_dalek::edwards::EdwardsPoint;
-#[cfg(any(feature = "alloc", feature = "std"))]
+#[cfg(all(feature = "batch", any(feature = "alloc", feature = "std")))]
 use curve25519_dalek::scalar::Scalar;
 
 pub use crate::constants::*;
@@ -48,7 +48,7 @@ pub use crate::signature::*;
 /// * `messages` is a slice of byte slices, one per signed message.
 /// * `signatures` is a slice of `Signature`s.
 /// * `public_keys` is a slice of `PublicKey`s.
-/// * `csprng` is an implementation of `Rng + CryptoRng`, such as `rand::rngs::ThreadRng`.
+/// * `csprng` is an implementation of `Rng + CryptoRng`.
 ///
 /// # Panics
 ///
@@ -65,17 +65,16 @@ pub use crate::signature::*;
 ///
 /// ```
 /// extern crate ed25519_dalek;
-/// extern crate rand;
+/// extern crate rand_os;
 ///
 /// use ed25519_dalek::verify_batch;
 /// use ed25519_dalek::Keypair;
 /// use ed25519_dalek::PublicKey;
 /// use ed25519_dalek::Signature;
-/// use rand::thread_rng;
-/// use rand::rngs::ThreadRng;
+/// use rand_os::OsRng;
 ///
 /// # fn main() {
-/// let mut csprng: ThreadRng = thread_rng();
+/// let mut csprng: OsRng = OsRng::new().unwrap();
 /// let keypairs: Vec<Keypair> = (0..64).map(|_| Keypair::generate(&mut csprng)).collect();
 /// let msg: &[u8] = b"They're good dogs Brant";
 /// let messages: Vec<&[u8]> = (0..64).map(|_| msg).collect();
@@ -86,7 +85,7 @@ pub use crate::signature::*;
 /// assert!(result.is_ok());
 /// # }
 /// ```
-#[cfg(any(feature = "alloc", feature = "std"))]
+#[cfg(all(feature = "batch", any(feature = "alloc", feature = "std")))]
 #[allow(non_snake_case)]
 pub fn verify_batch(
     messages: &[&[u8]],
@@ -217,12 +216,14 @@ impl Keypair {
     /// # Example
     ///
     /// ```
+    /// extern crate rand_core;
     /// extern crate rand_os;
     /// extern crate ed25519_dalek;
     ///
     /// # #[cfg(feature = "std")]
     /// # fn main() {
     ///
+    /// use rand_core::{CryptoRng, RngCore};
     /// use rand_os::OsRng;
     /// use ed25519_dalek::Keypair;
     /// use ed25519_dalek::Signature;
@@ -238,7 +239,7 @@ impl Keypair {
     ///
     /// # Input
     ///
-    /// A CSPRNG with a `fill_bytes()` method, e.g. `rand_chacha::ChaChaRng`.
+    /// A CSPRNG with a `fill_bytes()` method, e.g. `rand_os::OsRng`.
     ///
     /// The caller must also supply a hash function which implements the
     /// `Digest` and `Default` traits, and which returns 512 bits of output.
@@ -282,17 +283,17 @@ impl Keypair {
     ///
     /// ```
     /// extern crate ed25519_dalek;
-    /// extern crate rand;
+    /// extern crate rand_os;
     ///
     /// use ed25519_dalek::Digest;
     /// use ed25519_dalek::Keypair;
     /// use ed25519_dalek::Sha512;
     /// use ed25519_dalek::Signature;
-    /// use rand::thread_rng;
+    /// use rand_os::OsRng;
     ///
     /// # #[cfg(feature = "std")]
     /// # fn main() {
-    /// let mut csprng = thread_rng();
+    /// let mut csprng = OsRng::new().unwrap();
     /// let keypair: Keypair = Keypair::generate(&mut csprng);
     /// let message: &[u8] = b"All I want is to pet all of the dogs.";
     ///
@@ -329,17 +330,17 @@ impl Keypair {
     ///
     /// ```
     /// # extern crate ed25519_dalek;
-    /// # extern crate rand;
+    /// # extern crate rand_os;
     /// #
     /// # use ed25519_dalek::Digest;
     /// # use ed25519_dalek::Keypair;
     /// # use ed25519_dalek::Signature;
     /// # use ed25519_dalek::Sha512;
-    /// # use rand::thread_rng;
+    /// # use rand_os::OsRng;
     /// #
     /// # #[cfg(feature = "std")]
     /// # fn main() {
-    /// # let mut csprng = thread_rng();
+    /// # let mut csprng: OsRng = OsRng::new().unwrap();
     /// # let keypair: Keypair = Keypair::generate(&mut csprng);
     /// # let message: &[u8] = b"All I want is to pet all of the dogs.";
     /// # let mut prehashed: Sha512 = Sha512::new();
@@ -400,17 +401,17 @@ impl Keypair {
     ///
     /// ```
     /// extern crate ed25519_dalek;
-    /// extern crate rand;
+    /// extern crate rand_os;
     ///
     /// use ed25519_dalek::Digest;
     /// use ed25519_dalek::Keypair;
     /// use ed25519_dalek::Signature;
     /// use ed25519_dalek::Sha512;
-    /// use rand::thread_rng;
+    /// use rand_os::OsRng;
     ///
     /// # #[cfg(feature = "std")]
     /// # fn main() {
-    /// let mut csprng = thread_rng();
+    /// let mut csprng: OsRng = OsRng::new().unwrap();
     /// let keypair: Keypair = Keypair::generate(&mut csprng);
     /// let message: &[u8] = b"All I want is to pet all of the dogs.";
     ///
diff --git a/src/lib.rs b/src/lib.rs
index 9b72ac8..1007b6c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,12 +19,13 @@
 //! the operating system's builtin PRNG:
 //!
 //! ```
+//! extern crate rand_core;
 //! extern crate rand_os;
 //! extern crate ed25519_dalek;
 //!
 //! # #[cfg(feature = "std")]
 //! # fn main() {
-//! use rand::Rng;
+//! use rand_core::RngCore;
 //! use rand_os::OsRng;
 //! use ed25519_dalek::Keypair;
 //! use ed25519_dalek::Signature;
@@ -40,14 +41,15 @@
 //! We can now use this `keypair` to sign a message:
 //!
 //! ```
-//! # extern crate rand;
+//! # extern crate rand_core;
+//! # extern crate rand_os;
 //! # extern crate ed25519_dalek;
 //! # fn main() {
-//! # use rand::Rng;
-//! # use rand::thread_rng;
+//! # use rand_core::RngCore;
+//! # use rand_os::OsRng;
 //! # use ed25519_dalek::Keypair;
 //! # use ed25519_dalek::Signature;
-//! # let mut csprng = thread_rng();
+//! # let mut csprng = OsRng::new().unwrap();
 //! # let keypair: Keypair = Keypair::generate(&mut csprng);
 //! let message: &[u8] = b"This is a test of the tsunami alert system.";
 //! let signature: Signature = keypair.sign(message);
@@ -58,14 +60,15 @@
 //! that `message`:
 //!
 //! ```
-//! # extern crate rand;
+//! # extern crate rand_core;
+//! # extern crate rand_os;
 //! # extern crate ed25519_dalek;
 //! # fn main() {
-//! # use rand::Rng;
-//! # use rand::thread_rng;
+//! # use rand_core::RngCore;
+//! # use rand_os::OsRng;
 //! # use ed25519_dalek::Keypair;
 //! # use ed25519_dalek::Signature;
-//! # let mut csprng = thread_rng();
+//! # let mut csprng = OsRng::new().unwrap();
 //! # let keypair: Keypair = Keypair::generate(&mut csprng);
 //! # let message: &[u8] = b"This is a test of the tsunami alert system.";
 //! # let signature: Signature = keypair.sign(message);
@@ -77,15 +80,16 @@
 //! verify this signature:
 //!
 //! ```
-//! # extern crate rand;
+//! # extern crate rand_core;
+//! # extern crate rand_os;
 //! # extern crate ed25519_dalek;
 //! # fn main() {
-//! # use rand::Rng;
-//! # use rand::thread_rng;
+//! # use rand_core::RngCore;
+//! # use rand_os::OsRng;
 //! # use ed25519_dalek::Keypair;
 //! # use ed25519_dalek::Signature;
 //! use ed25519_dalek::PublicKey;
-//! # let mut csprng = thread_rng();
+//! # let mut csprng = OsRng::new().unwrap();
 //! # let keypair: Keypair = Keypair::generate(&mut csprng);
 //! # let message: &[u8] = b"This is a test of the tsunami alert system.";
 //! # let signature: Signature = keypair.sign(message);
@@ -104,14 +108,15 @@
 //! verify your signatures!)
 //!
 //! ```
-//! # extern crate rand;
+//! # extern crate rand_core;
+//! # extern crate rand_os;
 //! # extern crate ed25519_dalek;
 //! # fn main() {
-//! # use rand::Rng;
-//! # use rand::thread_rng;
+//! # use rand_core::RngCore;
+//! # use rand_os::OsRng;
 //! # use ed25519_dalek::{Keypair, Signature, PublicKey};
 //! use ed25519_dalek::{PUBLIC_KEY_LENGTH, SECRET_KEY_LENGTH, KEYPAIR_LENGTH, SIGNATURE_LENGTH};
-//! # let mut csprng = thread_rng();
+//! # let mut csprng = OsRng::new().unwrap();
 //! # let keypair: Keypair = Keypair::generate(&mut csprng);
 //! # let message: &[u8] = b"This is a test of the tsunami alert system.";
 //! # let signature: Signature = keypair.sign(message);
@@ -127,14 +132,15 @@
 //! And similarly, decoded from bytes with `::from_bytes()`:
 //!
 //! ```
-//! # extern crate rand;
+//! # extern crate rand_core;
+//! # extern crate rand_os;
 //! # extern crate ed25519_dalek;
-//! # use rand::Rng;
-//! # use rand::thread_rng;
+//! # use rand_core::RngCore;
+//! # use rand_os::OsRng;
 //! # use ed25519_dalek::{Keypair, Signature, PublicKey, SecretKey, SignatureError};
 //! # use ed25519_dalek::{PUBLIC_KEY_LENGTH, SECRET_KEY_LENGTH, KEYPAIR_LENGTH, SIGNATURE_LENGTH};
 //! # fn do_test() -> Result<(SecretKey, PublicKey, Keypair, Signature), SignatureError> {
-//! # let mut csprng = thread_rng();
+//! # let mut csprng = OsRng::new().unwrap();
 //! # let keypair_orig: Keypair = Keypair::generate(&mut csprng);
 //! # let message: &[u8] = b"This is a test of the tsunami alert system.";
 //! # let signature_orig: Signature = keypair_orig.sign(message);
@@ -169,7 +175,8 @@
 //! For example, using [bincode](https://github.com/TyOverby/bincode):
 //!
 //! ```
-//! # extern crate rand;
+//! # extern crate rand_core;
+//! # extern crate rand_os;
 //! # extern crate ed25519_dalek;
 //! # #[cfg(feature = "serde")]
 //! extern crate serde;
@@ -178,11 +185,11 @@
 //!
 //! # #[cfg(feature = "serde")]
 //! # fn main() {
-//! # use rand::Rng;
-//! # use rand::thread_rng;
+//! # use rand_core::RngCore;
+//! # use rand_os::OsRng;
 //! # use ed25519_dalek::{Keypair, Signature, PublicKey};
 //! use bincode::{serialize, Infinite};
-//! # let mut csprng = thread_rng();
+//! # let mut csprng = OsRng::new().unwrap();
 //! # let keypair: Keypair = Keypair::generate(&mut csprng);
 //! # let message: &[u8] = b"This is a test of the tsunami alert system.";
 //! # let signature: Signature = keypair.sign(message);
@@ -200,7 +207,8 @@
 //! recipient may deserialise them and verify:
 //!
 //! ```
-//! # extern crate rand;
+//! # extern crate rand_core;
+//! # extern crate rand_os;
 //! # extern crate ed25519_dalek;
 //! # #[cfg(feature = "serde")]
 //! # extern crate serde;
@@ -209,13 +217,13 @@
 //! #
 //! # #[cfg(feature = "serde")]
 //! # fn main() {
-//! # use rand::Rng;
-//! # use rand::thread_rng;
+//! # use rand_core::RngCore;
+//! # use rand_os::OsRng;
 //! # use ed25519_dalek::{Keypair, Signature, PublicKey};
 //! # use bincode::{serialize, Infinite};
 //! use bincode::{deserialize};
 //!
-//! # let mut csprng = thread_rng();
+//! # let mut csprng = OsRng::new().unwrap();
 //! # let keypair: Keypair = Keypair::generate(&mut csprng);
 //! let message: &[u8] = b"This is a test of the tsunami alert system.";
 //! # let signature: Signature = keypair.sign(message);
@@ -250,10 +258,10 @@ extern crate std;
 extern crate clear_on_drop;
 extern crate curve25519_dalek;
 extern crate failure;
-#[cfg(any(feature = "std", test))]
+#[cfg(all(feature = "batch", any(feature = "std", feature = "alloc", test)))]
 extern crate rand;
-#[cfg(test)]
-extern crate rand_chacha;
+#[cfg(any(feature = "std", test))]
+extern crate rand_os;
 extern crate rand_core;
 #[cfg(feature = "serde")]
 extern crate serde;
diff --git a/src/secret.rs b/src/secret.rs
index 3e1a5d8..b3c0e0a 100644
--- a/src/secret.rs
+++ b/src/secret.rs
@@ -126,14 +126,12 @@ impl SecretKey {
     ///
     /// ```
     /// extern crate rand_os;
-    /// extern crate sha2;
     /// extern crate ed25519_dalek;
     ///
     /// # #[cfg(feature = "std")]
     /// # fn main() {
     /// #
     /// use rand_os::OsRng;
-    /// use sha2::Sha512;
     /// use ed25519_dalek::PublicKey;
     /// use ed25519_dalek::SecretKey;
     /// use ed25519_dalek::Signature;
@@ -149,18 +147,17 @@ impl SecretKey {
     /// Afterwards, you can generate the corresponding public:
     ///
     /// ```
-    /// # extern crate rand;
+    /// # extern crate rand_os;
     /// # extern crate ed25519_dalek;
     /// #
     /// # fn main() {
     /// #
-    /// # use rand::Rng;
-    /// # use rand::thread_rng;
+    /// # use rand_os::OsRng;
     /// # use ed25519_dalek::PublicKey;
     /// # use ed25519_dalek::SecretKey;
     /// # use ed25519_dalek::Signature;
     /// #
-    /// # let mut csprng = thread_rng();
+    /// # let mut csprng = OsRng::new().unwrap();
     /// # let secret_key: SecretKey = SecretKey::generate(&mut csprng);
     ///
     /// let public_key: PublicKey = (&secret_key).into();
@@ -172,7 +169,7 @@ impl SecretKey {
     /// A CSPRNG with a `fill_bytes()` method, e.g. `rand::OsRng`
     pub fn generate<T>(csprng: &mut T) -> SecretKey
     where
-        T: CryptoRng + Rng,
+        T: CryptoRng + RngCore,
     {
         let mut sk: SecretKey = SecretKey([0u8; 32]);
 
@@ -273,18 +270,18 @@ impl<'a> From<&'a SecretKey> for ExpandedSecretKey {
     /// # Examples
     ///
     /// ```
-    /// # extern crate rand;
+    /// # extern crate rand_core;
+    /// # extern crate rand_os;
     /// # extern crate sha2;
     /// # extern crate ed25519_dalek;
     /// #
     /// # fn main() {
     /// #
-    /// use rand::Rng;
-    /// use rand::thread_rng;
-    /// use sha2::Sha512;
+    /// use rand_core::RngCore;
+    /// use rand_os::OsRng;
     /// use ed25519_dalek::{SecretKey, ExpandedSecretKey};
     ///
-    /// let mut csprng = thread_rng();
+    /// let mut csprng = OsRng::new().unwrap();
     /// let secret_key: SecretKey = SecretKey::generate(&mut csprng);
     /// let expanded_secret_key: ExpandedSecretKey = ExpandedSecretKey::from(&secret_key);
     /// # }
@@ -329,7 +326,6 @@ impl ExpandedSecretKey {
     /// # fn main() {
     /// #
     /// use rand_os::OsRng;
-    /// use sha2::Sha512;
     /// use ed25519_dalek::{SecretKey, ExpandedSecretKey};
     ///
     /// let mut csprng: OsRng = OsRng::new().unwrap();
@@ -340,7 +336,7 @@ impl ExpandedSecretKey {
     /// assert!(&expanded_secret_key_bytes[..] != &[0u8; 64][..]);
     /// # }
     /// #
-    /// # #[cfg(any(not(feature = "sha2"), not(feature = "std")))]
+    /// # #[cfg(not(feature = "std"))]
     /// # fn main() { }
     /// ```
     #[inline]
@@ -384,13 +380,13 @@ impl ExpandedSecretKey {
     /// # Ok(expanded_secret_key_again)
     /// # }
     /// #
-    /// # #[cfg(all(feature = "sha2", feature = "std"))]
+    /// # #[cfg(feature = "std")]
     /// # fn main() {
     /// #     let result = do_test();
     /// #     assert!(result.is_ok());
     /// # }
     /// #
-    /// # #[cfg(any(not(feature = "sha2"), not(feature = "std")))]
+    /// # #[cfg(not(feature = "std"))]
     /// # fn main() { }
     /// ```
     #[inline]
diff --git a/tests/ed25519.rs b/tests/ed25519.rs
index d849e41..555b952 100644
--- a/tests/ed25519.rs
+++ b/tests/ed25519.rs
@@ -13,15 +13,14 @@
 extern crate bincode;
 extern crate ed25519_dalek;
 extern crate hex;
-extern crate rand;
+extern crate rand_os;
 extern crate sha2;
 
 use ed25519_dalek::*;
 
 use hex::FromHex;
 
-use rand::thread_rng;
-use rand::rngs::ThreadRng;
+use rand_os::OsRng;
 
 use sha2::Sha512;
 
@@ -117,7 +116,6 @@ mod integrations {
 
     #[test]
     fn sign_verify() {  // TestSignVerify
-        let mut csprng: ThreadRng;
         let keypair: Keypair;
         let good_sig: Signature;
         let bad_sig:  Signature;
@@ -125,7 +123,8 @@ mod integrations {
         let good: &[u8] = "test message".as_bytes();
         let bad:  &[u8] = "wrong message".as_bytes();
 
-        csprng  = thread_rng();
+        let mut csprng: OsRng = OsRng::new().unwrap();
+
         keypair  = Keypair::generate(&mut csprng);
         good_sig = keypair.sign(&good);
         bad_sig  = keypair.sign(&bad);
@@ -140,7 +139,6 @@ mod integrations {
 
     #[test]
     fn ed25519ph_sign_verify() {
-        let mut csprng: ThreadRng;
         let keypair: Keypair;
         let good_sig: Signature;
         let bad_sig:  Signature;
@@ -148,6 +146,8 @@ mod integrations {
         let good: &[u8] = b"test message";
         let bad:  &[u8] = b"wrong message";
 
+        let mut csprng: OsRng = OsRng::new().unwrap();
+
         // ugh… there's no `impl Copy for Sha512`… i hope we can all agree these are the same hashes
         let mut prehashed_good1: Sha512 = Sha512::default();
         prehashed_good1.input(good);
@@ -163,7 +163,6 @@ mod integrations {
 
         let context: &[u8] = b"testing testing 1 2 3";
 
-        csprng   = thread_rng();
         keypair  = Keypair::generate(&mut csprng);
         good_sig = keypair.sign_prehashed(prehashed_good1, Some(context));
         bad_sig  = keypair.sign_prehashed(prehashed_bad1,  Some(context));
@@ -176,6 +175,7 @@ mod integrations {
                 "Verification of a signature on a different message passed!");
     }
 
+    #[cfg(feature = "batch")]
     #[test]
     fn verify_batch_seven_signatures() {
         let messages: [&[u8]; 7] = [
@@ -186,7 +186,7 @@ mod integrations {
             b"Fuck dumbin' it down, spit ice, skip jewellery: Molotov cocktails on me like accessories.",
             b"Hey, I never cared about your bucks, so if I run up with a mask on, probably got a gas can too.",
             b"And I'm not here to fill 'er up. Nope, we came to riot, here to incite, we don't want any of your stuff.", ];
-        let mut csprng: ThreadRng = thread_rng();
+        let mut csprng: OsRng = OsRng::new().unwrap();
         let mut keypairs: Vec<Keypair> = Vec::new();
         let mut signatures: Vec<Signature> = Vec::new();
 
@@ -204,7 +204,7 @@ mod integrations {
 
     #[test]
     fn pubkey_from_secret_and_expanded_secret() {
-        let mut csprng = thread_rng();
+        let mut csprng = OsRng::new().unwrap();
         let secret: SecretKey = SecretKey::generate(&mut csprng);
         let expanded_secret: ExpandedSecretKey = (&secret).into();
         let public_from_secret: PublicKey = (&secret).into(); // XXX eww