diff --git a/src/entropy_rng.rs b/src/entropy_rng.rs
index b6e19d4e4f..67a033a9c8 100644
--- a/src/entropy_rng.rs
+++ b/src/entropy_rng.rs
@@ -10,7 +10,7 @@
 
 //! Entropy generator, or wrapper around external generators
 
-use rand_core::{RngCore, Error, impls};
+use rand_core::{RngCore, CryptoRng, Error, impls};
 use {OsRng, JitterRng};
 
 /// An RNG provided specifically for seeding PRNGs.
@@ -140,6 +140,8 @@ impl RngCore for EntropyRng {
     }
 }
 
+impl CryptoRng for EntropyRng {}
+
 #[cfg(test)]
 mod test {
     use super::*;
diff --git a/src/lib.rs b/src/lib.rs
index 651a44d208..c4e0ed2209 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -270,7 +270,7 @@ extern crate rand_core;
 use core::{marker, mem, slice};
 
 // re-exports from rand-core
-pub use rand_core::{RngCore, CryptoRng, SeedableRng};
+pub use rand_core::{RngCore, BlockRngCore, CryptoRng, SeedableRng};
 pub use rand_core::{ErrorKind, Error};
 
 // external rngs
@@ -865,6 +865,8 @@ impl SeedableRng for StdRng {
     }
 }
 
+impl CryptoRng for StdRng {}
+
 /// An RNG recommended when small state, cheap initialization and good
 /// performance are required. The PRNG algorithm in `SmallRng` is chosen to be
 /// efficient on the current platform, **without consideration for cryptography