diff --git a/Cargo.lock b/Cargo.lock
index 4ff58c9..e503905 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -455,7 +455,7 @@ name = "crypto"
 version = "0.1.0"
 dependencies = [
  "failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "hex 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hex 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "proptest 0.9.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "ring 0.13.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -674,7 +674,7 @@ dependencies = [
 
 [[package]]
 name = "hex"
-version = "0.4.0"
+version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -2236,7 +2236,7 @@ dependencies = [
 "checksum futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)" = "1b980f2816d6ee8673b6517b52cb0e808a180efc92e5c19d02cdda79066703ef"
 "checksum futures-cpupool 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "ab90cde24b3319636588d0c35fe03b1333857621051837ed769faefb4c2162e4"
 "checksum h2 0.1.20 (registry+https://github.com/rust-lang/crates.io-index)" = "2b53def7bb0253af7718036fe9338c15defd209136819464384f3a553e07481b"
-"checksum hex 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "023b39be39e3a2da62a94feb433e91e8bcd37676fbc8bea371daf52b7a769a3e"
+"checksum hex 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "644f9158b2f133fd50f5fb3242878846d9eb792e445c893805ff0e3824006e35"
 "checksum hostname 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "21ceb46a83a85e824ef93669c8b390009623863b5c195d1ba747292c0c72f94e"
 "checksum http 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)" = "d6ccf5ede3a895d8856620237b2f02972c1bbc78d2965ad7fe8838d4a0ed41f0"
 "checksum http-body 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6741c859c1b2463a423a1dbce98d418e6c3c3fc720fb0d45528657320920292d"
diff --git a/crypto/Cargo.toml b/crypto/Cargo.toml
index 543e8bb..05d2545 100644
--- a/crypto/Cargo.toml
+++ b/crypto/Cargo.toml
@@ -6,7 +6,7 @@ license = "MIT/Apache-2.0"
 
 [dependencies]
 failure = "0.1.7"
-hex = "0.4.0"
+hex = "0.4.2"
 ring = "0.13.5"
 
 [dev-dependencies]