diff --git a/Cargo.toml b/Cargo.toml
index 47c47d6..9f39ab8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -34,12 +34,12 @@ travis-ci = { repository = "dalek-cryptography/x25519-dalek", branch = "master"}
 features = ["nightly", "reusable_secrets", "serde"]
 
 [dependencies]
-curve25519-dalek = { version = "3", default-features = false }
-rand_core = { version = "0.5", default-features = false }
+curve25519-dalek = { git="ssh://git@github.com/dalek-cryptography/curve25519-dalek", rev="39dbaea"}
+rand_core = { version = "=0.6", default-features = false, features = ["getrandom"] }
 # `serde` is renamed to `our_serde` in order to avoid a name collision between
 # importing the serde dependency and enabling the curve25519-dalek/serde feature
 our_serde = { package = "serde", version = "1", default-features = false, optional = true, features = ["derive"] }
-zeroize = { version = "=1.3", default-features = false, features = ["zeroize_derive"] }
+zeroize = { version = "=1.5", default-features = false, features = ["zeroize_derive"] }
 
 [dev-dependencies]
 bincode = "1"
@@ -50,12 +50,7 @@ name = "x25519"
 harness = false
 
 [features]
-default = ["std", "u64_backend"]
+default = ["std"]
 serde = ["our_serde", "curve25519-dalek/serde"]
-std = ["curve25519-dalek/std"]
-nightly = ["curve25519-dalek/nightly"]
+std = []
 reusable_secrets = []
-u64_backend = ["curve25519-dalek/u64_backend"]
-u32_backend = ["curve25519-dalek/u32_backend"]
-fiat_u64_backend = ["curve25519-dalek/fiat_u64_backend"]
-fiat_u32_backend = ["curve25519-dalek/fiat_u32_backend"]