diff --git a/doc/shadowsocks-libev.asciidoc b/doc/shadowsocks-libev.asciidoc
index fd18eaa0..9d5d5d80 100644
--- a/doc/shadowsocks-libev.asciidoc
+++ b/doc/shadowsocks-libev.asciidoc
@@ -50,9 +50,10 @@ Set the password. The server and the client should use the same password.
 -m <encrypt_method>::
 Set the cipher.
 +
-*Shadowsocks-libev* accepts 18 different ciphers:
+*Shadowsocks-libev* accepts 21 different ciphers:
 +
-table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb, bf-cfb,
+table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb,
+aes-128-ctr, aes-192-ctr, aes-256-ctr, bf-cfb,
 camellia-128-cfb, camellia-192-cfb, camellia-256-cfb, cast5-cfb, des-cfb,
 idea-cfb, rc2-cfb, seed-cfb, salsa20, chacha20 and chacha20-ietf.
 +
diff --git a/doc/ss-local.asciidoc b/doc/ss-local.asciidoc
index b626c763..cc6d3f6f 100644
--- a/doc/ss-local.asciidoc
+++ b/doc/ss-local.asciidoc
@@ -43,9 +43,10 @@ Set the password. The server and the client should use the same password.
 -m <encrypt_method>::
 Set the cipher.
 +
-*Shadowsocks-libev* accepts 18 different ciphers:
+*Shadowsocks-libev* accepts 21 different ciphers:
 +
-table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb, bf-cfb,
+table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb,
+aes-128-ctr, aes-192-ctr, aes-256-ctr, bf-cfb,
 camellia-128-cfb, camellia-192-cfb, camellia-256-cfb, cast5-cfb, des-cfb,
 idea-cfb, rc2-cfb, seed-cfb, salsa20, chacha20 and chacha20-ietf.
 +
diff --git a/doc/ss-manager.asciidoc b/doc/ss-manager.asciidoc
index aae28c9e..0f8c6f5e 100644
--- a/doc/ss-manager.asciidoc
+++ b/doc/ss-manager.asciidoc
@@ -41,9 +41,10 @@ Set the password. The server and the client should use the same password.
 -m <encrypt_method>::
 Set the cipher.
 +
-*Shadowsocks-libev* accepts 18 different ciphers:
+*Shadowsocks-libev* accepts 21 different ciphers:
 +
-table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb, bf-cfb,
+table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb,
+aes-128-ctr, aes-192-ctr, aes-256-ctr, bf-cfb,
 camellia-128-cfb, camellia-192-cfb, camellia-256-cfb, cast5-cfb, des-cfb,
 idea-cfb, rc2-cfb, seed-cfb, salsa20, chacha20 and chacha20-ietf.
 +
diff --git a/doc/ss-redir.asciidoc b/doc/ss-redir.asciidoc
index 76e075b3..f54490d0 100644
--- a/doc/ss-redir.asciidoc
+++ b/doc/ss-redir.asciidoc
@@ -45,9 +45,10 @@ password.
 -m <encrypt_method>::
 Set the cipher.
 +
-*Shadowsocks-libev* accepts 18 different ciphers:
+*Shadowsocks-libev* accepts 21 different ciphers:
 +
-table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb, bf-cfb,
+table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb,
+aes-128-ctr, aes-192-ctr, aes-256-ctr, bf-cfb,
 camellia-128-cfb, camellia-192-cfb, camellia-256-cfb, cast5-cfb, des-cfb,
 idea-cfb, rc2-cfb, seed-cfb, salsa20, chacha20 and chacha20-ietf.
 +
diff --git a/doc/ss-server.asciidoc b/doc/ss-server.asciidoc
index 1a929839..139a7263 100644
--- a/doc/ss-server.asciidoc
+++ b/doc/ss-server.asciidoc
@@ -41,9 +41,10 @@ Set the password. The server and the client should use the same password.
 -m <encrypt_method>::
 Set the cipher.
 +
-*Shadowsocks-libev* accepts 18 different ciphers:
+*Shadowsocks-libev* accepts 21 different ciphers:
 +
-table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb, bf-cfb,
+table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb,
+aes-128-ctr, aes-192-ctr, aes-256-ctr, bf-cfb,
 camellia-128-cfb, camellia-192-cfb, camellia-256-cfb, cast5-cfb, des-cfb,
 idea-cfb, rc2-cfb, seed-cfb, salsa20, chacha20 and chacha20-ietf.
 +
diff --git a/doc/ss-tunnel.asciidoc b/doc/ss-tunnel.asciidoc
index ad4e69a9..7b44f229 100644
--- a/doc/ss-tunnel.asciidoc
+++ b/doc/ss-tunnel.asciidoc
@@ -44,9 +44,10 @@ Set the password. The server and the client should use the same password.
 -m <encrypt_method>::
 Set the cipher.
 +
-*Shadowsocks-libev* accepts 18 different ciphers:
+*Shadowsocks-libev* accepts 21 different ciphers:
 +
-table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb, bf-cfb,
+table, rc4, rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb,
+aes-128-ctr, aes-192-ctr, aes-256-ctr, bf-cfb,
 camellia-128-cfb, camellia-192-cfb, camellia-256-cfb, cast5-cfb, des-cfb,
 idea-cfb, rc2-cfb, seed-cfb, salsa20, chacha20 and chacha20-ietf.
 +
diff --git a/src/utils.c b/src/utils.c
index 1aaaaba9..f16775fa 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -243,6 +243,8 @@ usage()
         "       -m <encrypt_method>        Encrypt method: table, rc4, rc4-md5,\n");
     printf(
         "                                  aes-128-cfb, aes-192-cfb, aes-256-cfb,\n");
+    printf(
+        "                                  aes-128-ctr, aes-192-ctr, aes-256-ctr,\n");
     printf(
         "                                  bf-cfb, camellia-128-cfb, camellia-192-cfb,\n");
     printf(