diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 429d016..9121f70 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,14 +16,14 @@ jobs:
   fmt:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
-      - uses: actions-rs/toolchain@v1
+      - uses: actions/checkout@544eadc6bf3d226fd7a7a9f0dc5b5bf7ca0675b9 # v1
+      - uses: actions-rs/toolchain@63eb9591781c46a70274cb3ebdf190fce92702e8 # v1
         with:
           toolchain: stable
           profile: minimal
           components: rustfmt
           override: true
-      - uses: actions-rs/cargo@v1
+      - uses: actions-rs/cargo@e7f754b8e09f70ad8eb2c5aebf61e58e8403b210 # v1
         with:
           command: fmt
           args: --all -- --check
@@ -31,14 +31,14 @@ jobs:
   clippy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
-      - uses: actions-rs/toolchain@v1
+      - uses: actions/checkout@544eadc6bf3d226fd7a7a9f0dc5b5bf7ca0675b9 # v1
+      - uses: actions-rs/toolchain@63eb9591781c46a70274cb3ebdf190fce92702e8 # v1
         with:
           toolchain: stable
           profile: minimal
           components: clippy
           override: true
-      - uses: actions-rs/cargo@v1
+      - uses: actions-rs/cargo@e7f754b8e09f70ad8eb2c5aebf61e58e8403b210 # v1
         with:
           command: clippy
           args: --workspace --tests --examples
@@ -46,14 +46,14 @@ jobs:
   docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@master
-      - uses: actions-rs/toolchain@v1
+      - uses: actions/checkout@61b9e3751b92087fd0b06925ba6dd6314e06f089 # master
+      - uses: actions-rs/toolchain@63eb9591781c46a70274cb3ebdf190fce92702e8 # v1
         with:
           toolchain: nightly
           profile: minimal
           components: rust-docs
           override: true
-      - uses: actions-rs/cargo@v1
+      - uses: actions-rs/cargo@e7f754b8e09f70ad8eb2c5aebf61e58e8403b210 # v1
         with:
           command: doc
           args: --no-deps
@@ -67,12 +67,12 @@ jobs:
     env:
       RUSTFLAGS: -Dwarnings
     steps:
-      - uses: actions/checkout@master
-      - uses: actions-rs/toolchain@v1
+      - uses: actions/checkout@61b9e3751b92087fd0b06925ba6dd6314e06f089 # master
+      - uses: actions-rs/toolchain@63eb9591781c46a70274cb3ebdf190fce92702e8 # v1
         with:
           toolchain: ${{ matrix.rust }}
           profile: minimal
           override: true
-      - uses: actions-rs/cargo@v1
+      - uses: actions-rs/cargo@e7f754b8e09f70ad8eb2c5aebf61e58e8403b210 # v1
         with:
           command: test