diff --git a/Cargo.toml b/Cargo.toml
index 5a200e5..18db298 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "ecies"
-version = "0.2.1"
+version = "0.2.2"
 # docs
 authors = ["Weiliang Li <to.be.impressive@gmail.com>"]
 description = "Elliptic Curve Integrated Encryption Scheme for secp256k1 in Rust"
@@ -25,11 +25,11 @@ libsecp256k1 = "0.7.0"
 sha2 = "0.9.8"
 
 # openssl aes
-openssl = {version = "0.10.32", optional = true}
+openssl = {version = "0.10.38", optional = true}
 
 # pure rust aes
-aes-gcm = {version = "0.9.0", optional = true}
-typenum = {version = "1.12.0", optional = true}
+aes-gcm = {version = "0.9.4", optional = true}
+typenum = {version = "1.14.0", optional = true}
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 getrandom = {version = "0.2.3", features = ["js"]}
@@ -43,8 +43,8 @@ default = ["openssl"]
 pure = ["aes-gcm", "typenum"]
 
 [dev-dependencies]
-criterion = "0.3.3"
-hex = "0.4.2"
+criterion = "0.3.5"
+hex = "0.4.3"
 
 [target.'cfg(target_arch = "wasm32")'.dev-dependencies]
 wasm-bindgen-test = "0.3.28"
@@ -52,7 +52,7 @@ wasm-bindgen-test = "0.3.28"
 [target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
 futures-util = "0.3.17"
 reqwest = "0.11.6"
-tokio = {version = "1.13.0", features = ["rt-multi-thread"]}
+tokio = {version = "1.14.0", features = ["rt-multi-thread"]}
 
 [[bench]]
 harness = false
diff --git a/README.md b/README.md
index ec684ea..c3cad2f 100644
--- a/README.md
+++ b/README.md
@@ -77,8 +77,69 @@ Following dependencies are audited:
 - [aes-gcm](https://research.nccgroup.com/2020/02/26/public-report-rustcrypto-aes-gcm-and-chacha20poly1305-implementation-review/)
 - [OpenSSL](https://ostif.org/the-ostif-and-quarkslab-audit-of-openssl-is-complete/)
 
+## Benchmark
+
+The result shows that the pure Rust backend is around 20% ~ 50% slower compared to OpenSSL on MacBook Pro mid-2015 (2.8 GHz Quad-Core Intel Core i7).
+
+### OpenSSL backend
+
+```bash
+$ cargo bench --no-default-features --features openssl
+encrypt 100M            time:   [110.25 ms 115.77 ms 120.22 ms]
+                        change: [-10.123% -3.0504% +4.2342%] (p = 0.44 > 0.05)
+                        No change in performance detected.
+
+encrypt 200M            time:   [435.22 ms 450.50 ms 472.17 ms]
+                        change: [-7.5254% +3.6572% +14.508%] (p = 0.56 > 0.05)
+                        No change in performance detected.
+Found 1 outliers among 10 measurements (10.00%)
+  1 (10.00%) high mild
+
+decrypt 100M            time:   [60.439 ms 66.276 ms 70.959 ms]
+                        change: [+0.1986% +7.7620% +15.995%] (p = 0.08 > 0.05)
+                        No change in performance detected.
+
+decrypt 200M            time:   [182.10 ms 185.85 ms 190.63 ms]
+                        change: [-4.8452% +5.2114% +16.370%] (p = 0.40 > 0.05)
+                        No change in performance detected.
+Found 1 outliers among 10 measurements (10.00%)
+  1 (10.00%) high severe
+
+```
+
+### Pure Rust backend
+
+```bash
+$ export RUSTFLAGS="-Ctarget-cpu=sandybridge -Ctarget-feature=+aes,+sse2,+sse4.1,+ssse3"
+$ cargo bench --no-default-features --features pure
+encrypt 100M            time:   [196.85 ms 201.97 ms 205.67 ms]
+                        change: [-9.8235% -7.9098% -5.9849%] (p = 0.00 < 0.05)
+                        Performance has improved.
+Found 1 outliers among 10 measurements (10.00%)
+  1 (10.00%) low severe
+
+encrypt 200M            time:   [554.62 ms 585.01 ms 599.71 ms]
+                        change: [-15.036% -11.698% -8.6460%] (p = 0.00 < 0.05)
+                        Performance has improved.
+
+decrypt 100M            time:   [131.26 ms 134.39 ms 140.54 ms]
+                        change: [-3.9509% +2.9485% +10.198%] (p = 0.42 > 0.05)
+                        No change in performance detected.
+
+decrypt 200M            time:   [288.13 ms 296.64 ms 311.78 ms]
+                        change: [-16.887% -13.038% -8.6679%] (p = 0.00 < 0.05)
+                        Performance has improved.
+Found 1 outliers among 10 measurements (10.00%)
+  1 (10.00%) high mild
+```
+
 ## Release Notes
 
+### 0.2.2
+
+- Bump dependencies
+- Migrate to edition 2021
+
 ### 0.2.1
 
 - Revamp error handling
diff --git a/bench/simple.rs b/bench/simple.rs
index 6f05f26..24479b9 100644
--- a/bench/simple.rs
+++ b/bench/simple.rs
@@ -27,7 +27,7 @@ fn criterion_benchmark(c: &mut Criterion) {
 
 criterion_group! {
     name = benches;
-    config = Criterion::default().sample_size(10).measurement_time(Duration::new(20, 0));
+    config = Criterion::default().sample_size(10).measurement_time(Duration::new(30, 0));
     targets = criterion_benchmark
 }
 criterion_main!(benches);