diff --git a/src/rust/Cargo.lock b/src/rust/Cargo.lock
index 769e2c39c..a16ffc4ef 100644
--- a/src/rust/Cargo.lock
+++ b/src/rust/Cargo.lock
@@ -5,7 +5,7 @@ dependencies = [
  "digest 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "external 0.0.1",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.5.0-pre.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.5.0-pre.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smartlist 0.0.1",
  "tor_allocate 0.0.1",
@@ -55,10 +55,10 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.5.0-pre.1"
+version = "0.5.0-pre.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rand_core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.2.0-pre.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -66,6 +66,11 @@ name = "rand_core"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "rand_core"
+version = "0.2.0-pre.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "smartlist"
 version = "0.0.1"
@@ -114,6 +119,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum digest 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "00a49051fef47a72c9623101b19bd71924a45cca838826caae3eaa4d00772603"
 "checksum generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ef25c5683767570c2bbd7deba372926a55eaae9982d7726ee2a1050239d45b9d"
 "checksum libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)" = "f54263ad99207254cf58b5f701ecb432c717445ea2ee8af387334bdd1a03fdff"
-"checksum rand 0.5.0-pre.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7d7a7728c20bfd9fcc6e713e748e787c3d00e5ffd139b3ad1b5be92c5dfbaad5"
+"checksum rand 0.5.0-pre.2 (registry+https://github.com/rust-lang/crates.io-index)" = "3795e4701d9628a63a84d0289e66279883b40df165fca7caed7b87122447032a"
 "checksum rand_core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0224284424a4b818387b58d59336c288f99b48f69681aa60cc681fe038bbca5d"
+"checksum rand_core 0.2.0-pre.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c7255ffbdb188d5be1a69b6f9f3cf187de4207430b9e79ed5b76458a6b20de9a"
 "checksum typenum 1.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "13a99dc6780ef33c78780b826cf9d2a78840b72cae9474de4bcaf9051e60ebbd"
diff --git a/src/rust/crypto/Cargo.toml b/src/rust/crypto/Cargo.toml
index 8b489dfb4..508c288aa 100644
--- a/src/rust/crypto/Cargo.toml
+++ b/src/rust/crypto/Cargo.toml
@@ -21,7 +21,7 @@ tor_allocate = { path = "../tor_allocate" }
 tor_log = { path = "../tor_log" }
 
 [dev-dependencies]
-rand = { version = "=0.5.0-pre.1", default-features = false }
+rand = { version = "=0.5.0-pre.2", default-features = false }
 
 [features]
 testing = ["tor_log/testing"]