diff --git a/Cargo.lock b/Cargo.lock
index 0558a71d4fdb..1c020290d641 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -128,9 +128,9 @@ dependencies = [
 
 [[package]]
 name = "bumpalo"
-version = "3.8.0"
+version = "3.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f1e260c3a9040a7c19a12468758f4c16f31a81a1fe087482be9570ec864bb6c"
+checksum = "a4a45a46ab1f2412e53d3a0ade76ffad2025804294569aae387231a0cd6e0899"
 
 [[package]]
 name = "byte-tools"
@@ -189,9 +189,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "3.0.5"
+version = "3.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6f34b09b9ee8c7c7b400fe2f8df39cafc9538b03d6ba7f4ae13e4cb90bfbb7d"
+checksum = "12e8611f9ae4e068fa3e56931fded356ff745e70987ff76924a6e0ab1c8ef2e3"
 dependencies = [
  "atty",
  "bitflags",
@@ -205,9 +205,9 @@ dependencies = [
 
 [[package]]
 name = "cmake"
-version = "0.1.46"
+version = "0.1.48"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7b858541263efe664aead4a5209a4ae5c5d2811167d4ed4ee0944503f8d2089"
+checksum = "e8ad8cef104ac57b68b89df3208164d228503abbdce70f6880ffa3d970e7443a"
 dependencies = [
  "cc",
 ]
@@ -230,9 +230,9 @@ checksum = "5827cebf4670468b8772dd191856768aedcb1b0278a04f989f7766351917b9dc"
 
 [[package]]
 name = "crossbeam-channel"
-version = "0.5.1"
+version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "06ed27e177f16d65f0f0c22a213e17c696ace5dd64b14258b52f9417ccb52db4"
+checksum = "e54ea8bc3fb1ee042f5aace6e3c6e025d3874866da222930f70ce62aceba0bfa"
 dependencies = [
  "cfg-if",
  "crossbeam-utils",
@@ -240,9 +240,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.8.5"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d82cfc11ce7f2c3faef78d8a684447b40d503d9681acebed6cb728d45940c4db"
+checksum = "cfcae03edb34f947e64acdb1c33ec169824e20657e9ecb61cef6c8c74dcb8120"
 dependencies = [
  "cfg-if",
  "lazy_static",
@@ -362,6 +362,15 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
 
+[[package]]
+name = "fastrand"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "779d043b6a0b90cc4c0ed7ee380a6504394cee7efd7db050e3774eee387324b2"
+dependencies = [
+ "instant",
+]
+
 [[package]]
 name = "filetime"
 version = "0.2.15"
@@ -413,9 +422,9 @@ checksum = "2022715d62ab30faffd124d40b76f4134a550a87792276512b18d63272333394"
 
 [[package]]
 name = "fsevent-sys"
-version = "4.0.0"
+version = "4.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c0e564d24da983c053beff1bb7178e237501206840a3e6bf4e267b9e8ae734a"
+checksum = "76ee7a02da4d231650c7cea31349b889be2f45ddb3ef3032d2ec8185f6313fd2"
 dependencies = [
  "libc",
 ]
@@ -520,9 +529,9 @@ dependencies = [
 
 [[package]]
 name = "getrandom"
-version = "0.2.3"
+version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
+checksum = "418d37c8b1d42553c93648be529cb70f920d3baf8ef469b74b9638df426e0b4c"
 dependencies = [
  "cfg-if",
  "libc",
@@ -531,9 +540,9 @@ dependencies = [
 
 [[package]]
 name = "h2"
-version = "0.3.9"
+version = "0.3.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f072413d126e57991455e0a922b31e4c8ba7c2ffbebf6b78b4f8521397d65cd"
+checksum = "0c9de88456263e249e241fcd211d3954e2c9b0ef7ccfc235a444eb367cae3689"
 dependencies = [
  "bytes",
  "fnv",
@@ -660,9 +669,9 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "1.7.0"
+version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bc633605454125dec4b66843673f01c7df2b89479b32e0ed634e43a91cff62a5"
+checksum = "282a6247722caba404c065016bbfa522806e51714c34f5dfc3e4a3a46fcb4223"
 dependencies = [
  "autocfg",
  "hashbrown",
@@ -1076,9 +1085,9 @@ dependencies = [
 
 [[package]]
 name = "openssl-probe"
-version = "0.1.4"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28988d872ab76095a6e6ac88d99b54fd267702734fd7ffe610ca27f533ddb95a"
+checksum = "ff011a302c396a5197692431fc1948019154afc178baf7d8e37367442a4601cf"
 
 [[package]]
 name = "openssl-sys"
@@ -1095,9 +1104,9 @@ dependencies = [
 
 [[package]]
 name = "ordered-float"
-version = "2.9.0"
+version = "2.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8aa3d135650b150c29f0c3e385896f9d3ceb42d2d87b02f0d7a8cbd0fc7e19a6"
+checksum = "7940cf2ca942593318d07fcf2596cdca60a85c9e7fab408a5e21a4f9dcd40d87"
 dependencies = [
  "num-traits",
 ]
@@ -1634,6 +1643,7 @@ dependencies = [
  "notify",
  "once_cell",
  "pin-project",
+ "rand",
  "sendfd",
  "serde",
  "serde_json",
@@ -1760,9 +1770,9 @@ checksum = "9def91fd1e018fe007022791f865d0ccc9b3a0d5001e01aabb8b40e46000afb5"
 
 [[package]]
 name = "smallvec"
-version = "1.7.0"
+version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ecab6c735a6bb4139c0caafd0cc3635748bbb3acf4550e8138122099251f309"
+checksum = "f2dd574626839106c320a323308629dcb1acfc96e32a8cba364ddc61ac23ee83"
 
 [[package]]
 name = "snmalloc-rs"
@@ -1826,9 +1836,9 @@ checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
 
 [[package]]
 name = "syn"
-version = "1.0.84"
+version = "1.0.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ecb2e6da8ee5eb9a61068762a32fa9619cc591ceb055b3687f4cd4051ec2e06b"
+checksum = "a684ac3dcd8913827e18cd09a68384ee66c1de24157e3c556c9ab16d85695fb7"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1852,13 +1862,13 @@ checksum = "3b7ad73e635dd232c2c2106d59269f59a61de421cc6b95252d2d932094ff1f40"
 
 [[package]]
 name = "tempfile"
-version = "3.2.0"
+version = "3.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dac1c663cfc93810f88aed9b8941d48cabf856a1b111c29a40439018d870eb22"
+checksum = "5cdb1ef4eaeeaddc8fbd371e5017057064af0911902ef36b39801f67cc6d79e4"
 dependencies = [
  "cfg-if",
+ "fastrand",
  "libc",
- "rand",
  "redox_syscall 0.2.10",
  "remove_dir_all",
  "winapi",
diff --git a/crates/shadowsocks/Cargo.toml b/crates/shadowsocks/Cargo.toml
index 6808bde83970..6f78c75ae13a 100644
--- a/crates/shadowsocks/Cargo.toml
+++ b/crates/shadowsocks/Cargo.toml
@@ -48,6 +48,7 @@ spin = { version = "0.9", features = ["std"], optional = true }
 pin-project = "1.0"
 bloomfilter = { version = "1.0.8", optional = true }
 thiserror = "1.0"
+rand = "0.8"
 
 serde = { version = "1.0", features = ["derive"] }
 serde_urlencoded = "0.7"
diff --git a/crates/shadowsocks/src/context.rs b/crates/shadowsocks/src/context.rs
index 76d8fce5e588..ff55689015da 100644
--- a/crates/shadowsocks/src/context.rs
+++ b/crates/shadowsocks/src/context.rs
@@ -4,6 +4,7 @@ use std::{io, net::SocketAddr, sync::Arc};
 
 use byte_string::ByteStr;
 use log::warn;
+use rand::Rng;
 
 use crate::{
     config::{ReplayAttackPolicy, ServerType},
@@ -66,6 +67,20 @@ impl Context {
         loop {
             random_iv_or_salt(nonce);
 
+            // SECURITY: First 6 bytes of payload should be printable characters
+            // Observation shows that prepending 6 bytes of printable characters to random payload will exempt it from blocking.
+            // by 2022-01-13 gfw.report et al.
+            const SECURITY_PRINTABLE_PREFIX_LEN: usize = 6;
+            if nonce.len() >= SECURITY_PRINTABLE_PREFIX_LEN {
+                // Printable characters follows definition of isprint in C/C++
+                static ASCII_PRINTABLE_CHARS: &[u8] = br##"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~ "##;
+
+                let mut rng = rand::thread_rng();
+                for b in nonce.iter_mut().take(SECURITY_PRINTABLE_PREFIX_LEN) {
+                    *b = ASCII_PRINTABLE_CHARS[rng.gen_range::<usize, _>(0..ASCII_PRINTABLE_CHARS.len())];
+                }
+            }
+
             // Salt already exists, generate a new one.
             if unique && self.check_nonce_and_set(nonce) {
                 continue;