diff --git a/Cargo.lock b/Cargo.lock
index b3da9f5..001dc57 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "add-one"
@@ -118,14 +118,13 @@ checksum = "ac74c624d6b2d21f425f752262f42188365d7b8ff1aff74c82e45136510a4857"
 
 [[package]]
 name = "rand"
-version = "0.8.4"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
+checksum = "5ca0ecfa931c29007047d1bc58e623ab12e5590e8c7cc53200d5202b69266d8a"
 dependencies = [
  "libc",
  "rand_chacha",
  "rand_core",
- "rand_hc",
 ]
 
 [[package]]
@@ -147,15 +146,6 @@ dependencies = [
  "getrandom",
 ]
 
-[[package]]
-name = "rand_hc"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
-dependencies = [
- "rand_core",
-]
-
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"
diff --git a/rust-book/add-one/Cargo.toml b/rust-book/add-one/Cargo.toml
index de6538f..55637cc 100644
--- a/rust-book/add-one/Cargo.toml
+++ b/rust-book/add-one/Cargo.toml
@@ -7,4 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-rand = "0.8.4"
\ No newline at end of file
+rand = "0.8.6"
\ No newline at end of file
diff --git a/rust-book/ch2-guess/Cargo.toml b/rust-book/ch2-guess/Cargo.toml
index 154b3a3..3c969d7 100644
--- a/rust-book/ch2-guess/Cargo.toml
+++ b/rust-book/ch2-guess/Cargo.toml
@@ -7,4 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-rand = "0.8.4"
\ No newline at end of file
+rand = "0.8.6"
\ No newline at end of file