From 3645668bffe02b6b1f756354b5e40e197a530bc0 Mon Sep 17 00:00:00 2001
From: Marc Brinkmann <git@marcbrinkmann.de>
Date: Mon, 1 Oct 2018 12:25:31 +0200
Subject: [PATCH] Add an API that allows specifying the RNG to be used for
 encryption.

---
 src/lib.rs | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index e93d88b..1057656 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -101,9 +101,17 @@ impl PublicKey {
         self.verify_g2(sig, hash_g2(msg))
     }
 
-    /// Encrypts the message.
+    /// Encrypts the message using the OS random number generator.
+    ///
+    /// Uses the `OsRng` by default. To pass in a custom random number generator, use
+    /// `encrypt_with_rng()`.
     pub fn encrypt<M: AsRef<[u8]>>(&self, msg: M) -> Ciphertext {
-        let r: Fr = OsRng::new().expect(ERR_OS_RNG).gen();
+        self.encrypt_with_rng(&mut OsRng::new().expect(ERR_OS_RNG), msg)
+    }
+
+    /// Encrypts the message.
+    pub fn encrypt_with_rng<R: Rng, M: AsRef<[u8]>>(&self, rng: &mut R, msg: M) -> Ciphertext {
+        let r: Fr = rng.gen();
         let u = G1Affine::one().mul(r);
         let v: Vec<u8> = {
             let g = self.0.into_affine().mul(r);