diff --git a/Cargo.lock b/Cargo.lock
index 91ce94a..4091f25 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -233,9 +233,9 @@ checksum = "7f30e7476521f6f8af1a1c4c0b8cc94f0bee37d91763d0ca2665f299b6cd8aec"
 
 [[package]]
 name = "bytecount"
-version = "0.6.5"
+version = "0.6.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d1a12477b7237a01c11a80a51278165f9ba0edd28fa6db00a65ab230320dc58c"
+checksum = "e1e5f035d16fc623ae5f74981db80a439803888314e3a555fd6f04acd51a3205"
 
 [[package]]
 name = "byteorder"
@@ -300,9 +300,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.4.6"
+version = "4.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d04704f56c2cde07f43e8e2c154b43f216dc5c92fc98ada720177362f953b956"
+checksum = "ac495e00dcec98c83465d5ad66c5c4fabd652fd6686e7c6269b117e729a6f17b"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -310,9 +310,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.4.6"
+version = "4.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e231faeaca65ebd1ea3c737966bf858971cd38c3849107aa3ea7de90a804e45"
+checksum = "c77ed9a32a62e6ca27175d00d29d05ca32e396ea1eb5fb01d8256b669cec7663"
 dependencies = [
  "anstream",
  "anstyle",
@@ -322,9 +322,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.4.2"
+version = "4.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0862016ff20d69b84ef8247369fabf5c008a7417002411897d40ee1f4532b873"
+checksum = "cf9804afaaf59a91e75b022a30fb7229a7901f60c755489cc61c9b423b836442"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -334,9 +334,9 @@ dependencies = [
 
 [[package]]
 name = "clap_lex"
-version = "0.5.1"
+version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd7cc57abe963c6d3b9d8be5b06ba7c8957a930305ca90304f24ef040aa6f961"
+checksum = "702fc72eb24e5a1e48ce58027a675bc24edd52096d5397d4aea7c6dd9eca0bd1"
 
 [[package]]
 name = "colorchoice"
@@ -1729,7 +1729,7 @@ dependencies = [
 
 [[package]]
 name = "tiny-encrypt"
-version = "0.5.2"
+version = "0.5.3"
 dependencies = [
  "aes-gcm-stream",
  "base64",
diff --git a/Cargo.toml b/Cargo.toml
index 9caa5c3..abbe5c2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "tiny-encrypt"
-version = "0.5.2"
+version = "0.5.3"
 edition = "2021"
 license = "MIT"
 description = "A simple and tiny file encrypt tool"
diff --git a/README.md b/README.md
index 1f76936..49222c5 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,11 @@ Specification: [Tiny Encrypt Spec V1.1](https://github.com/OpenWebStandard/tiny-
 
 Repository address: https://git.hatter.ink/hatter/tiny-encrypt-rs mirror https://github.com/jht5945/tiny-encrypt-rs
 
+Set default encryption algorithm:
+```shell
+export TINY_ENCRYPT_DEFAULT_ALGORITHM='AES' # or CHACHA20
+```
+
 <br>
 
 Encrypt config `~/.tinyencrypt/config-rs.json`:
diff --git a/src/cmd_encrypt.rs b/src/cmd_encrypt.rs
index cbe3488..83e3221 100644
--- a/src/cmd_encrypt.rs
+++ b/src/cmd_encrypt.rs
@@ -10,7 +10,7 @@ use rsa::Pkcs1v15Encrypt;
 use rust_util::{debugging, failure, iff, information, opt_result, simple_error, success, XResult};
 use rust_util::util_time::UnixEpochTime;
 
-use crate::{consts, crypto_simple, util, util_enc_file, util_p256, util_p384, util_x25519};
+use crate::{crypto_cryptor, crypto_simple, util, util_enc_file, util_p256, util_p384, util_x25519};
 use crate::compress::GzStreamEncoder;
 use crate::config::{TinyEncryptConfig, TinyEncryptConfigEnvelop};
 use crate::consts::{
@@ -119,14 +119,7 @@ fn encrypt_single(path: &PathBuf, envelops: &[&TinyEncryptConfigEnvelop], cmd_en
         return Ok(0);
     }
 
-    let encryption_algorithm = cmd_encrypt.encryption_algorithm.as_deref()
-        .unwrap_or(consts::TINY_ENC_AES_GCM)
-        .to_lowercase();
-    let cryptor = match encryption_algorithm.as_str() {
-        "aes" | "aes/gcm" => Cryptor::Aes256Gcm,
-        "chacha20" | "chacha20/poly1305" => Cryptor::ChaCha20Poly1305,
-        _ => return simple_error!("Unknown encryption algorithm: {}, should be AES or CHACHA20", encryption_algorithm),
-    };
+    let cryptor = crypto_cryptor::get_cryptor_by_encryption_algorithm(&cmd_encrypt.encryption_algorithm)?;
     information!("Using encryption algorithm: {}", cryptor.get_name());
 
     util::require_file_exists(path)?;
@@ -184,11 +177,13 @@ fn encrypt_single(path: &PathBuf, envelops: &[&TinyEncryptConfigEnvelop], cmd_en
     let _ = util_enc_file::write_tiny_encrypt_meta(&mut file_out, &encrypt_meta, compress_meta)?;
 
     let compress_desc = iff!(cmd_encrypt.compress, " [with compress]", "");
-    let compress_level = iff!(cmd_encrypt.compress, &cmd_encrypt.compress_level, &None);
+
+    let compress_level = iff!(cmd_encrypt.compress,
+        Some(cmd_encrypt.compress_level.unwrap_or_else(|| Compression::default().level())), None);
     let start = Instant::now();
     encrypt_file(
         &mut file_in, file_metadata.len(), &mut file_out, cryptor,
-        &key.0, &nonce.0, compress_level,
+        &key.0, &nonce.0, &compress_level,
     )?;
     drop(file_out);
     let encrypt_duration = start.elapsed();
@@ -338,14 +333,14 @@ fn encrypt_envelop_shared_secret(cryptor: Cryptor,
                                  enc_type: &str,
                                  envelop: &TinyEncryptConfigEnvelop) -> XResult<TinyEncryptEnvelop> {
     let shared_key = util::simple_kdf(shared_secret);
-    let (_, nonce) = util::make_key256_and_nonce();
+    let nonce = util::make_nonce();
 
     let encrypted_key = crypto_simple::encrypt(
         cryptor, &shared_key, &nonce.0, key)?;
 
     let wrap_key = WrapKey {
         header: WrapKeyHeader {
-            kid: None, // Some(envelop.kid.clone()),
+            kid: None,
             enc: enc_type.to_string(),
             e_pub_key: util::encode_base64_url_no_pad(ephemeral_spki),
         },
@@ -357,7 +352,7 @@ fn encrypt_envelop_shared_secret(cryptor: Cryptor,
     Ok(TinyEncryptEnvelop {
         r#type: envelop.r#type,
         kid: envelop.kid.clone(),
-        desc: None, // envelop.desc.clone(),
+        desc: None,
         encrypted_key: encoded_wrap_key,
     })
 }
@@ -369,7 +364,7 @@ fn encrypt_envelop_pgp(key: &[u8], envelop: &TinyEncryptConfigEnvelop) -> XResul
     Ok(TinyEncryptEnvelop {
         r#type: envelop.r#type,
         kid: envelop.kid.clone(),
-        desc: None, // envelop.desc.clone(),
+        desc: None,
         encrypted_key: util::encode_base64(&encrypted_key),
     })
 }
diff --git a/src/consts.rs b/src/consts.rs
index 105ecda..887ae44 100644
--- a/src/consts.rs
+++ b/src/consts.rs
@@ -10,6 +10,7 @@ pub const ENC_CHACHA20_POLY1305_X25519: &str = "chacha20-poly1305-x25519";
 pub const TINY_ENC_FILE_EXT: &str = ".tinyenc";
 pub const TINY_ENC_CONFIG_FILE: &str = "~/.tinyencrypt/config-rs.json";
 
+pub const TINY_ENCRYPT_ENV_DEFAULT_ALGORITHM: &str = "TINY_ENCRYPT_DEFAULT_ALGORITHM";
 pub const TINY_ENC_AES_GCM: &str = "AES/GCM";
 pub const TINY_ENC_CHACHA20_POLY1305: &str = "CHACHA20/POLY1305";
 
diff --git a/src/crypto_cryptor.rs b/src/crypto_cryptor.rs
index 33ec568..d4aa54e 100644
--- a/src/crypto_cryptor.rs
+++ b/src/crypto_cryptor.rs
@@ -3,7 +3,7 @@ use chacha20_poly1305_stream::{ChaCha20Poly1305StreamDecryptor, ChaCha20Poly1305
 use rust_util::{opt_result, simple_error, XResult};
 use zeroize::Zeroize;
 
-use crate::consts;
+use crate::{consts, util_env};
 
 #[derive(Debug, Copy, Clone)]
 pub enum Cryptor {
@@ -152,6 +152,20 @@ impl Decryptor for ChaCha20Poly1305Decryptor {
     }
 }
 
+#[allow(clippy::redundant_closure)]
+pub fn get_cryptor_by_encryption_algorithm(encryption_algorithm: &Option<String>) -> XResult<Cryptor> {
+    let encryption_algorithm = encryption_algorithm.as_deref()
+        .or_else(|| util_env::get_default_encryption_algorithm())
+        .unwrap_or(consts::TINY_ENC_AES_GCM)
+        .to_lowercase();
+    let cryptor = match encryption_algorithm.as_str() {
+        "aes" | "aes/gcm" => Cryptor::Aes256Gcm,
+        "chacha20" | "chacha20/poly1305" => Cryptor::ChaCha20Poly1305,
+        _ => return simple_error!("Unknown encryption algorithm: {}, should be AES or CHACHA20", encryption_algorithm),
+    };
+    Ok(cryptor)
+}
+
 #[test]
 fn test_cryptor() {
     let key = [0u8; 32];
diff --git a/src/main.rs b/src/main.rs
index 5981822..9472054 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -11,6 +11,7 @@ use crate::cmd_version::CmdVersion;
 
 mod consts;
 mod util;
+mod util_env;
 mod util_digest;
 mod util_progress;
 mod util_piv;
diff --git a/src/util.rs b/src/util.rs
index 580905c..2549c5a 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -76,6 +76,11 @@ pub fn require_file_not_exists(path: impl AsRef<Path>) -> XResult<()> {
     }
 }
 
+pub fn make_nonce() -> SecVec {
+    let (_, nonce) = make_key256_and_nonce();
+    nonce
+}
+
 pub fn make_key256_and_nonce() -> (SecVec, SecVec) {
     let key: [u8; 32] = random();
     let nonce: [u8; 12] = random();
diff --git a/src/util_env.rs b/src/util_env.rs
new file mode 100644
index 0000000..3f7b93e
--- /dev/null
+++ b/src/util_env.rs
@@ -0,0 +1,16 @@
+use std::env;
+
+use crate::consts;
+
+pub fn get_default_encryption_algorithm() -> Option<&'static str> {
+    let env_default_algorithm = env::var(consts::TINY_ENCRYPT_ENV_DEFAULT_ALGORITHM).ok();
+    if let Some(env_algorithm) = env_default_algorithm {
+        let lower_default_algorithm = env_algorithm.to_lowercase();
+        match lower_default_algorithm.as_str() {
+            "aes" | "aes/gcm" => return Some(consts::TINY_ENC_AES_GCM),
+            "chacha20" | "chacha20/poly1305" => return Some(consts::TINY_ENC_CHACHA20_POLY1305),
+            _ => {}
+        }
+    }
+    None
+}
\ No newline at end of file