diff --git a/.gitignore b/.gitignore
index 0b36d7d..e6f83bd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,13 +29,17 @@ htmlcov
 
 .DS_Store
 .idea
+tags
 
 #Emacs
 .#*
+venv/
 
-#vscode
+# VS-code
+.vscode/
+
+# Pycharm
 .idea
-.vscode
 
 #ss
 config.json
diff --git a/setup.py b/setup.py
index b27c8eb..f41f481 100644
--- a/setup.py
+++ b/setup.py
@@ -7,7 +7,7 @@ with codecs.open('README.rst', encoding='utf-8') as f:
 
 setup(
     name="shadowsocks",
-    version="2.9.1",
+    version="3.0.0",
     license='http://www.apache.org/licenses/LICENSE-2.0',
     description="A fast tunnel proxy that help you get through firewalls",
     author='clowwindy',
diff --git a/shadowsocks/crypto/aead.py b/shadowsocks/crypto/aead.py
new file mode 100644
index 0000000..1ca06f2
--- /dev/null
+++ b/shadowsocks/crypto/aead.py
@@ -0,0 +1,285 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Void Copyright NO ONE
+#
+# Void License
+#
+# The code belongs to no one. Do whatever you want.
+# Forget about boring open source license.
+#
+# AEAD cipher for shadowsocks
+#
+
+from __future__ import absolute_import, division, print_function, \
+    with_statement
+
+from ctypes import create_string_buffer
+
+import hashlib
+from struct import pack, unpack
+
+from shadowsocks.crypto import hkdf
+from shadowsocks.common import ord, chr
+
+
+EVP_CTRL_GCM_SET_IVLEN = 0x9
+EVP_CTRL_GCM_GET_TAG = 0x10
+EVP_CTRL_GCM_SET_TAG = 0x11
+EVP_CTRL_CCM_SET_IVLEN = EVP_CTRL_GCM_SET_IVLEN
+EVP_CTRL_CCM_GET_TAG = EVP_CTRL_GCM_GET_TAG
+EVP_CTRL_CCM_SET_TAG = EVP_CTRL_GCM_SET_TAG
+
+EVP_CTRL_AEAD_SET_IVLEN = EVP_CTRL_GCM_SET_IVLEN
+EVP_CTRL_AEAD_SET_TAG = EVP_CTRL_GCM_SET_TAG
+EVP_CTRL_AEAD_GET_TAG = EVP_CTRL_GCM_GET_TAG
+
+AEAD_MSG_LEN_UNKNOWN = 0
+AEAD_CHUNK_SIZE_LEN = 2
+AEAD_CHUNK_SIZE_MASK = 0x3FFF
+
+CIPHER_NONCE_LEN = {
+    'aes-128-gcm': 12,
+    'aes-192-gcm': 12,
+    'aes-256-gcm': 12,
+    'chacha20-poly1305': 12,
+    'chacha20-ietf-poly1305': 12,
+    'xchacha20-ietf-poly1305': 24,
+}
+
+CIPHER_TAG_LEN = {
+    'aes-128-gcm': 16,
+    'aes-192-gcm': 16,
+    'aes-256-gcm': 16,
+    'chacha20-poly1305': 16,
+    'chacha20-ietf-poly1305': 16,
+    'xchacha20-ietf-poly1305': 16,
+}
+
+SUBKEY_INFO = b"ss-subkey"
+
+
+def nonce_increment(nonce, nlen):
+    """
+    Increase nonce by 1 in little endian
+    From libsodium sodium_increment():
+    for (; i < nlen; i++) {
+        c += (uint_fast16_t) n[i];
+        n[i] = (unsigned char) c;
+        c >>= 8;
+    }
+    :param nonce: string_buffer nonce
+    :param nlen: nonce length
+    :return: nonce plus by 1
+    """
+    c = 1
+    i = 0
+    # n = create_string_buffer(nlen)
+    while i < nlen:
+        c += ord(nonce[i])
+        nonce[i] = chr(c & 0xFF)
+        c >>= 8
+        i += 1
+    return  # n.raw
+
+
+class AeadCryptoBase(object):
+    """
+    Handles basic aead process of shadowsocks protocol
+
+    TCP Chunk (after encryption, *ciphertext*)
+    +--------------+---------------+--------------+------------+
+    |  *DataLen*   |  DataLen_TAG  |    *Data*    |  Data_TAG  |
+    +--------------+---------------+--------------+------------+
+    |      2       |     Fixed     |   Variable   |   Fixed    |
+    +--------------+---------------+--------------+------------+
+
+    UDP (after encryption, *ciphertext*)
+    +--------+-----------+-----------+
+    | NONCE  |  *Data*   |  Data_TAG |
+    +-------+-----------+-----------+
+    | Fixed  | Variable  |   Fixed   |
+    +--------+-----------+-----------+
+    """
+
+    def __init__(self, cipher_name, key, iv, op):
+        self._op = int(op)
+        self._salt = iv
+        self._nlen = CIPHER_NONCE_LEN[cipher_name]
+        self._nonce = create_string_buffer(self._nlen)
+        self._tlen = CIPHER_TAG_LEN[cipher_name]
+
+        crypto_hkdf = hkdf.Hkdf(iv, key, algorithm=hashlib.sha1)
+        self._skey = crypto_hkdf.expand(info=SUBKEY_INFO, length=len(key))
+        # _chunk['mlen']:
+        # -1, waiting data len header
+        # n, n > 0, waiting data
+        self._chunk = {'mlen': AEAD_MSG_LEN_UNKNOWN, 'data': b''}
+
+        self.encrypt_once = self.aead_encrypt
+        self.decrypt_once = self.aead_decrypt
+
+    def cipher_ctx_init(self):
+        """
+        Increase nonce to make it unique for the same key
+        :return: void
+        """
+        nonce_increment(self._nonce, self._nlen)
+        # print("".join("%02x" % ord(b) for b in self._nonce))
+
+    def aead_encrypt(self, data):
+        """
+        Encrypt data with authenticate tag
+
+        :param data: plain text
+        :return: cipher text with tag
+        """
+        raise Exception("Must implement aead_encrypt method")
+
+    def encrypt_chunk(self, data):
+        """
+        Encrypt a chunk for TCP chunks
+
+        :param data: str
+        :return: (str, int)
+        """
+        plen = len(data)
+        l = AEAD_CHUNK_SIZE_LEN + plen + self._tlen * 2
+
+        # network byte order
+        ctext = self.aead_encrypt(pack("!H", plen & AEAD_CHUNK_SIZE_MASK))
+        if len(ctext) != AEAD_CHUNK_SIZE_LEN + self._tlen:
+            raise Exception("data length invalid")
+
+        self.cipher_ctx_init()
+        ctext += self.aead_encrypt(data)
+        if len(ctext) != l:
+            raise Exception("data length invalid")
+
+        self.cipher_ctx_init()
+        return ctext, l
+
+    def encrypt(self, data):
+        """
+        Encrypt data, for TCP divided into chunks
+        For UDP data, call aead_encrypt instead
+
+        :param data: str data bytes
+        :return: str encrypted data
+        """
+        plen = len(data)
+        if plen <= AEAD_CHUNK_SIZE_MASK:
+            ctext, _ = self.encrypt_chunk(data)
+            return ctext
+        ctext, clen = b"", 0
+        while plen > 0:
+            mlen = plen if plen < AEAD_CHUNK_SIZE_MASK \
+                else AEAD_CHUNK_SIZE_MASK
+            r, l = self.encrypt_chunk(data[:mlen])
+            ctext += r
+            clen += l
+            data = data[mlen:]
+            plen -= mlen
+
+        return ctext
+
+    def aead_decrypt(self, data):
+        """
+        Decrypt data and authenticate tag
+
+        :param data: str cipher text with tag
+        :return: str plain text
+        """
+        raise Exception("Must implement aead_decrypt method")
+
+    def decrypt_chunk_size(self, data):
+        """
+        Decrypt chunk size
+
+        :param data: str encrypted msg
+        :return: (int, str) msg length and remaining encrypted data
+        """
+        if self._chunk['mlen'] > 0:
+            return self._chunk['mlen'], data
+        data = self._chunk['data'] + data
+        self._chunk['data'] = b""
+
+        hlen = AEAD_CHUNK_SIZE_LEN + self._tlen
+        if hlen > len(data):
+            self._chunk['data'] = data
+            return 0, b""
+        plen = self.aead_decrypt(data[:hlen])
+        plen, = unpack("!H", plen)
+        if plen & AEAD_CHUNK_SIZE_MASK != plen or plen <= 0:
+            raise Exception('Invalid message length')
+
+        self.cipher_ctx_init()
+        return plen, data[hlen:]
+
+    def decrypt_chunk_payload(self, plen, data):
+        """
+        Decrypted encrypted msg payload
+
+        :param plen: int payload length
+        :param data: str encrypted data
+        :return: (str, str) plain text and remaining encrypted data
+        """
+        data = self._chunk['data'] + data
+        if len(data) < plen + self._tlen:
+            self._chunk['mlen'] = plen
+            self._chunk['data'] = data
+            return b"", b""
+        self._chunk['mlen'] = AEAD_MSG_LEN_UNKNOWN
+        self._chunk['data'] = b""
+
+        plaintext = self.aead_decrypt(data[:plen + self._tlen])
+
+        if len(plaintext) != plen:
+            raise Exception("plaintext length invalid")
+
+        self.cipher_ctx_init()
+
+        return plaintext, data[plen + self._tlen:]
+
+    def decrypt_chunk(self, data):
+        """
+        Decrypt a TCP chunk
+
+        :param data: str encrypted msg
+        :return: (str, str) decrypted msg and remaining encrypted data
+        """
+        plen, data = self.decrypt_chunk_size(data)
+        if plen <= 0:
+            return b"", b""
+        return self.decrypt_chunk_payload(plen, data)
+
+    def decrypt(self, data):
+        """
+        Decrypt data for TCP data divided into chunks
+        For UDP data, call aead_decrypt instead
+
+        :param data: str
+        :return: str
+        """
+        ptext, left = self.decrypt_chunk(data)
+        while len(left) > 0:
+            pnext, left = self.decrypt_chunk(left)
+            ptext += pnext
+        return ptext
+
+
+def test_nonce_increment():
+    buf = create_string_buffer(12)
+    print("".join("%02x" % ord(b) for b in buf))
+    nonce_increment(buf, 12)
+    nonce_increment(buf, 12)
+    nonce_increment(buf, 12)
+    nonce_increment(buf, 12)
+    print("".join("%02x" % ord(b) for b in buf))
+    for i in range(256):
+        nonce_increment(buf, 12)
+        print("".join("%02x" % ord(b) for b in buf))
+
+
+if __name__ == '__main__':
+    test_nonce_increment()
diff --git a/shadowsocks/crypto/hkdf.py b/shadowsocks/crypto/hkdf.py
new file mode 100644
index 0000000..11998e6
--- /dev/null
+++ b/shadowsocks/crypto/hkdf.py
@@ -0,0 +1,98 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Void Copyright NO ONE
+#
+# Void License
+#
+# The code belongs to no one. Do whatever you want.
+# Forget about boring open source license.
+#
+# HKDF for AEAD ciphers
+#
+
+from __future__ import division
+
+import hmac
+import hashlib
+import sys
+
+if sys.version_info[0] == 3:
+    def buffer(x):
+        return x
+
+
+def hkdf_extract(salt, input_key_material, algorithm=hashlib.sha256):
+    """
+    Extract a pseudorandom key suitable for use with hkdf_expand
+    from the input_key_material and a salt using HMAC with the
+    provided hash (default SHA-256).
+
+    salt should be a random, application-specific byte string. If
+    salt is None or the empty string, an all-zeros string of the same
+    length as the hash's block size will be used instead per the RFC.
+
+    See the HKDF draft RFC and paper for usage notes.
+    """
+    hash_len = algorithm().digest_size
+    if salt is None or len(salt) == 0:
+        salt = bytearray((0,) * hash_len)
+    return hmac.new(bytes(salt), buffer(input_key_material), algorithm)\
+        .digest()
+
+
+def hkdf_expand(pseudo_random_key, info=b"", length=32,
+                algorithm=hashlib.sha256):
+    """
+    Expand `pseudo_random_key` and `info` into a key of length `bytes` using
+    HKDF's expand function based on HMAC with the provided hash (default
+    SHA-256). See the HKDF draft RFC and paper for usage notes.
+    """
+    hash_len = algorithm().digest_size
+    length = int(length)
+    if length > 255 * hash_len:
+        raise Exception("Cannot expand to more than 255 * %d = %d "
+                        "bytes using the specified hash function" %
+                        (hash_len, 255 * hash_len))
+    blocks_needed = length // hash_len \
+        + (0 if length % hash_len == 0 else 1)  # ceil
+    okm = b""
+    output_block = b""
+    for counter in range(blocks_needed):
+        output_block = hmac.new(
+            pseudo_random_key,
+            buffer(output_block + info + bytearray((counter + 1,))),
+            algorithm
+        ).digest()
+        okm += output_block
+    return okm[:length]
+
+
+class Hkdf(object):
+    """
+    Wrapper class for HKDF extract and expand functions
+    """
+
+    def __init__(self, salt, input_key_material, algorithm=hashlib.sha256):
+        """
+         Extract a pseudorandom key from `salt` and `input_key_material`
+         arguments.
+
+         See the HKDF draft RFC for guidance on setting these values.
+         The constructor optionally takes a `algorithm` argument defining
+         the hash function use, defaulting to hashlib.sha256.
+         """
+        self._hash = algorithm
+        self._prk = hkdf_extract(salt, input_key_material, self._hash)
+
+    def expand(self, info, length=32):
+        """
+        Generate output key material based on an `info` value
+
+        Arguments:
+        - info - context to generate the OKM
+        - length - length in bytes of the key to generate
+
+        See the HKDF draft RFC for guidance.
+        """
+        return hkdf_expand(self._prk, info, length, self._hash)
diff --git a/shadowsocks/crypto/openssl.py b/shadowsocks/crypto/openssl.py
index da7f177..50cdc22 100644
--- a/shadowsocks/crypto/openssl.py
+++ b/shadowsocks/crypto/openssl.py
@@ -22,6 +22,8 @@ from ctypes import c_char_p, c_int, c_long, byref,\
 
 from shadowsocks import common
 from shadowsocks.crypto import util
+from shadowsocks.crypto.aead import AeadCryptoBase, EVP_CTRL_AEAD_SET_IVLEN, \
+    nonce_increment, EVP_CTRL_AEAD_GET_TAG, EVP_CTRL_AEAD_SET_TAG
 
 __all__ = ['ciphers']
 
@@ -30,6 +32,8 @@ loaded = False
 
 buf_size = 2048
 
+CIPHER_ENC_UNCHANGED = -1
+
 
 def load_openssl():
     global loaded, libcrypto, buf, ctx_cleanup
@@ -45,10 +49,13 @@ def load_openssl():
 
     libcrypto.EVP_CipherInit_ex.argtypes = (c_void_p, c_void_p, c_char_p,
                                             c_char_p, c_char_p, c_int)
+    libcrypto.EVP_CIPHER_CTX_ctrl.argtypes = (c_void_p, c_int, c_int, c_void_p)
 
     libcrypto.EVP_CipherUpdate.argtypes = (c_void_p, c_void_p, c_void_p,
                                            c_char_p, c_int)
 
+    libcrypto.EVP_CipherFinal_ex.argtypes = (c_void_p, c_void_p, c_void_p)
+
     try:
         libcrypto.EVP_CIPHER_CTX_cleanup.argtypes = (c_void_p,)
         ctx_cleanup = libcrypto.EVP_CIPHER_CTX_cleanup
@@ -64,7 +71,7 @@ def load_openssl():
 
 
 def load_cipher(cipher_name):
-    func_name = 'EVP_' + cipher_name.replace('-', '_')
+    func_name = b'EVP_' + cipher_name.replace(b'-', b'_')
     if bytes != str:
         func_name = str(func_name, 'utf-8')
     cipher = getattr(libcrypto, func_name, None)
@@ -74,9 +81,13 @@ def load_cipher(cipher_name):
     return None
 
 
-class OpenSSLCrypto(object):
-    def __init__(self, cipher_name, key, iv, op):
+class OpenSSLCryptoBase(object):
+    """
+    OpenSSL crypto base class
+    """
+    def __init__(self, cipher_name):
         self._ctx = None
+        self._cipher = None
         if not loaded:
             load_openssl()
         cipher_name = common.to_bytes(cipher_name)
@@ -85,26 +96,30 @@ class OpenSSLCrypto(object):
             cipher = load_cipher(cipher_name)
         if not cipher:
             raise Exception('cipher %s not found in libcrypto' % cipher_name)
-        key_ptr = c_char_p(key)
-        iv_ptr = c_char_p(iv)
         self._ctx = libcrypto.EVP_CIPHER_CTX_new()
+        self._cipher = cipher
         if not self._ctx:
             raise Exception('can not create cipher context')
-        r = libcrypto.EVP_CipherInit_ex(self._ctx, cipher, None,
-                                        key_ptr, iv_ptr, c_int(op))
-        if not r:
-            self.clean()
-            raise Exception('can not initialize cipher context')
+
+        self.encrypt_once = self.update
+        self.decrypt_once = self.update
 
     def update(self, data):
+        """
+        Encrypt/decrypt data
+        :param data: str
+        :return: str
+        """
         global buf_size, buf
         cipher_out_len = c_long(0)
         l = len(data)
         if buf_size < l:
             buf_size = l * 2
             buf = create_string_buffer(buf_size)
-        libcrypto.EVP_CipherUpdate(self._ctx, byref(buf),
-                                   byref(cipher_out_len), c_char_p(data), l)
+        libcrypto.EVP_CipherUpdate(
+            self._ctx, byref(buf),
+            byref(cipher_out_len), c_char_p(data), l
+        )
         # buf is copied to a str object when we access buf.raw
         return buf.raw[:cipher_out_len.value]
 
@@ -117,39 +132,190 @@ class OpenSSLCrypto(object):
             libcrypto.EVP_CIPHER_CTX_free(self._ctx)
 
 
+class OpenSSLAeadCrypto(OpenSSLCryptoBase, AeadCryptoBase):
+    """
+    Implement OpenSSL Aead mode: gcm, ocb
+    """
+    def __init__(self, cipher_name, key, iv, op):
+        super(OpenSSLAeadCrypto, self).__init__(cipher_name)
+        AeadCryptoBase.__init__(self, cipher_name, key, iv, op)
+
+        r = libcrypto.EVP_CipherInit_ex(
+            self._ctx,
+            self._cipher, None,
+            None, None, c_int(op)
+        )
+        if not r:
+            self.clean()
+            raise Exception('can not initialize cipher context')
+
+        r = libcrypto.EVP_CIPHER_CTX_ctrl(
+            self._ctx,
+            c_int(EVP_CTRL_AEAD_SET_IVLEN),
+            c_int(self._nlen),
+            None
+        )
+        if not r:
+            raise Exception('Set ivlen failed')
+
+        self.cipher_ctx_init()
+
+    def cipher_ctx_init(self):
+        """
+        Need init cipher context after EVP_CipherFinal_ex to reuse context
+        :return: void
+        """
+        key_ptr = c_char_p(self._skey)
+        iv_ptr = c_char_p(self._nonce.raw)
+
+        r = libcrypto.EVP_CipherInit_ex(
+            self._ctx,
+            None, None,
+            key_ptr, iv_ptr,
+            c_int(CIPHER_ENC_UNCHANGED)
+        )
+        if not r:
+            self.clean()
+            raise Exception('can not initialize cipher context')
+
+        nonce_increment(self._nonce, self._nlen)
+        # print("".join("%02x" % ord(b) for b in self._nonce))
+
+    def set_tag(self, tag):
+        """
+        Set tag before decrypt any data (update)
+        :param tag: authenticated tag
+        :return: void
+        """
+        tag_len = self._tlen
+        r = libcrypto.EVP_CIPHER_CTX_ctrl(
+            self._ctx,
+            c_int(EVP_CTRL_AEAD_SET_TAG),
+            c_int(tag_len), c_char_p(tag)
+        )
+        if not r:
+            raise Exception('Set tag failed')
+
+    def get_tag(self):
+        """
+        Get authenticated tag, called after EVP_CipherFinal_ex
+        :return: str
+        """
+        tag_len = self._tlen
+        tag_buf = create_string_buffer(tag_len)
+        r = libcrypto.EVP_CIPHER_CTX_ctrl(
+            self._ctx,
+            c_int(EVP_CTRL_AEAD_GET_TAG),
+            c_int(tag_len), byref(tag_buf)
+        )
+        if not r:
+            raise Exception('Get tag failed')
+        return tag_buf.raw[:tag_len]
+
+    def final(self):
+        """
+        Finish encrypt/decrypt a chunk (<= 0x3FFF)
+        :return: str
+        """
+        global buf_size, buf
+        cipher_out_len = c_long(0)
+        r = libcrypto.EVP_CipherFinal_ex(
+            self._ctx,
+            byref(buf), byref(cipher_out_len)
+        )
+        if not r:
+            # print(self._nonce.raw, r, cipher_out_len)
+            raise Exception('Verify data failed')
+        return buf.raw[:cipher_out_len.value]
+
+    def aead_encrypt(self, data):
+        """
+        Encrypt data with authenticate tag
+
+        :param data: plain text
+        :return: cipher text with tag
+        """
+        ctext = self.update(data) + self.final() + self.get_tag()
+        return ctext
+
+    def aead_decrypt(self, data):
+        """
+        Decrypt data and authenticate tag
+
+        :param data: cipher text with tag
+        :return: plain text
+        """
+        clen = len(data)
+        if clen < self._tlen:
+            raise Exception('Data too short')
+
+        self.set_tag(data[clen - self._tlen:])
+        plaintext = self.update(data[:clen - self._tlen]) + self.final()
+        return plaintext
+
+
+class OpenSSLStreamCrypto(OpenSSLCryptoBase):
+    """
+    Crypto for stream modes: cfb, ofb, ctr
+    """
+    def __init__(self, cipher_name, key, iv, op):
+        super(OpenSSLStreamCrypto, self).__init__(cipher_name)
+        key_ptr = c_char_p(key)
+        iv_ptr = c_char_p(iv)
+        r = libcrypto.EVP_CipherInit_ex(self._ctx, self._cipher, None,
+                                        key_ptr, iv_ptr, c_int(op))
+        if not r:
+            self.clean()
+            raise Exception('can not initialize cipher context')
+        self.encrypt = self.update
+        self.decrypt = self.update
+
+
 ciphers = {
-    'aes-128-cfb': (16, 16, OpenSSLCrypto),
-    'aes-192-cfb': (24, 16, OpenSSLCrypto),
-    'aes-256-cfb': (32, 16, OpenSSLCrypto),
-    'aes-128-ofb': (16, 16, OpenSSLCrypto),
-    'aes-192-ofb': (24, 16, OpenSSLCrypto),
-    'aes-256-ofb': (32, 16, OpenSSLCrypto),
-    'aes-128-ctr': (16, 16, OpenSSLCrypto),
-    'aes-192-ctr': (24, 16, OpenSSLCrypto),
-    'aes-256-ctr': (32, 16, OpenSSLCrypto),
-    'aes-128-cfb8': (16, 16, OpenSSLCrypto),
-    'aes-192-cfb8': (24, 16, OpenSSLCrypto),
-    'aes-256-cfb8': (32, 16, OpenSSLCrypto),
-    'aes-128-cfb1': (16, 16, OpenSSLCrypto),
-    'aes-192-cfb1': (24, 16, OpenSSLCrypto),
-    'aes-256-cfb1': (32, 16, OpenSSLCrypto),
-    'bf-cfb': (16, 8, OpenSSLCrypto),
-    'camellia-128-cfb': (16, 16, OpenSSLCrypto),
-    'camellia-192-cfb': (24, 16, OpenSSLCrypto),
-    'camellia-256-cfb': (32, 16, OpenSSLCrypto),
-    'cast5-cfb': (16, 8, OpenSSLCrypto),
-    'des-cfb': (8, 8, OpenSSLCrypto),
-    'idea-cfb': (16, 8, OpenSSLCrypto),
-    'rc2-cfb': (16, 8, OpenSSLCrypto),
-    'rc4': (16, 0, OpenSSLCrypto),
-    'seed-cfb': (16, 16, OpenSSLCrypto),
+    'aes-128-cfb': (16, 16, OpenSSLStreamCrypto),
+    'aes-192-cfb': (24, 16, OpenSSLStreamCrypto),
+    'aes-256-cfb': (32, 16, OpenSSLStreamCrypto),
+    'aes-128-gcm': (16, 16, OpenSSLAeadCrypto),
+    'aes-192-gcm': (24, 24, OpenSSLAeadCrypto),
+    'aes-256-gcm': (32, 32, OpenSSLAeadCrypto),
+    'aes-128-ofb': (16, 16, OpenSSLStreamCrypto),
+    'aes-192-ofb': (24, 16, OpenSSLStreamCrypto),
+    'aes-256-ofb': (32, 16, OpenSSLStreamCrypto),
+    'aes-128-ctr': (16, 16, OpenSSLStreamCrypto),
+    'aes-192-ctr': (24, 16, OpenSSLStreamCrypto),
+    'aes-256-ctr': (32, 16, OpenSSLStreamCrypto),
+    'aes-128-cfb8': (16, 16, OpenSSLStreamCrypto),
+    'aes-192-cfb8': (24, 16, OpenSSLStreamCrypto),
+    'aes-256-cfb8': (32, 16, OpenSSLStreamCrypto),
+    'aes-128-cfb1': (16, 16, OpenSSLStreamCrypto),
+    'aes-192-cfb1': (24, 16, OpenSSLStreamCrypto),
+    'aes-256-cfb1': (32, 16, OpenSSLStreamCrypto),
+    'bf-cfb': (16, 8, OpenSSLStreamCrypto),
+    'camellia-128-cfb': (16, 16, OpenSSLStreamCrypto),
+    'camellia-192-cfb': (24, 16, OpenSSLStreamCrypto),
+    'camellia-256-cfb': (32, 16, OpenSSLStreamCrypto),
+    'cast5-cfb': (16, 8, OpenSSLStreamCrypto),
+    'des-cfb': (8, 8, OpenSSLStreamCrypto),
+    'idea-cfb': (16, 8, OpenSSLStreamCrypto),
+    'rc2-cfb': (16, 8, OpenSSLStreamCrypto),
+    'rc4': (16, 0, OpenSSLStreamCrypto),
+    'seed-cfb': (16, 16, OpenSSLStreamCrypto),
 }
 
 
 def run_method(method):
 
-    cipher = OpenSSLCrypto(method, b'k' * 32, b'i' * 16, 1)
-    decipher = OpenSSLCrypto(method, b'k' * 32, b'i' * 16, 0)
+    cipher = OpenSSLStreamCrypto(method, b'k' * 32, b'i' * 16, 1)
+    decipher = OpenSSLStreamCrypto(method, b'k' * 32, b'i' * 16, 0)
+
+    util.run_cipher(cipher, decipher)
+
+
+def run_aead_method(method, key_len=16):
+
+    key_len = int(key_len)
+    cipher = OpenSSLAeadCrypto(method, b'k' * key_len, b'i' * key_len, 1)
+    decipher = OpenSSLAeadCrypto(method, b'k' * key_len, b'i' * key_len, 0)
 
     util.run_cipher(cipher, decipher)
 
@@ -158,6 +324,16 @@ def test_aes_128_cfb():
     run_method('aes-128-cfb')
 
 
+def test_aes_gcm(bits=128):
+    method = "aes-{0}-gcm".format(bits)
+    print(method, int(bits / 8))
+    run_aead_method(method, bits / 8)
+
+
+def test_aes_256_gcm():
+    test_aes_gcm(256)
+
+
 def test_aes_256_cfb():
     run_method('aes-256-cfb')
 
@@ -184,3 +360,7 @@ def test_rc4():
 
 if __name__ == '__main__':
     test_aes_128_cfb()
+    test_aes_gcm(128)
+    test_aes_gcm(192)
+    test_aes_gcm(256)
+    test_aes_256_gcm()
diff --git a/shadowsocks/crypto/rc4_md5.py b/shadowsocks/crypto/rc4_md5.py
index 1f07a82..2f7f22e 100644
--- a/shadowsocks/crypto/rc4_md5.py
+++ b/shadowsocks/crypto/rc4_md5.py
@@ -18,7 +18,6 @@ from __future__ import absolute_import, division, print_function, \
     with_statement
 
 import hashlib
-
 from shadowsocks.crypto import openssl
 
 __all__ = ['ciphers']
@@ -30,7 +29,7 @@ def create_cipher(alg, key, iv, op, key_as_bytes=0, d=None, salt=None,
     md5.update(key)
     md5.update(iv)
     rc4_key = md5.digest()
-    return openssl.OpenSSLCrypto(b'rc4', rc4_key, b'', op)
+    return openssl.OpenSSLStreamCrypto(b'rc4', rc4_key, b'', op)
 
 
 ciphers = {
diff --git a/shadowsocks/crypto/sodium.py b/shadowsocks/crypto/sodium.py
index b744e2c..48a459f 100644
--- a/shadowsocks/crypto/sodium.py
+++ b/shadowsocks/crypto/sodium.py
@@ -21,6 +21,7 @@ from ctypes import c_char_p, c_int, c_ulonglong, byref, c_ulong, \
     create_string_buffer, c_void_p
 
 from shadowsocks.crypto import util
+from shadowsocks.crypto.aead import AeadCryptoBase
 
 __all__ = ['ciphers']
 
@@ -59,6 +60,67 @@ def load_libsodium():
                                                              c_ulong,
                                                              c_char_p)
 
+    # chacha20-poly1305
+    libsodium.crypto_aead_chacha20poly1305_encrypt.restype = c_int
+    libsodium.crypto_aead_chacha20poly1305_encrypt.argtypes = (
+        c_void_p, c_void_p,     # c, clen
+        c_char_p, c_ulonglong,  # m, mlen
+        c_char_p, c_ulonglong,  # ad, adlen
+        c_char_p,               # nsec, not used
+        c_char_p, c_char_p      # npub, k
+    )
+    libsodium.crypto_aead_chacha20poly1305_decrypt.restype = c_int
+    libsodium.crypto_aead_chacha20poly1305_decrypt.argtypes = (
+        c_void_p, c_void_p,     # m, mlen
+        c_char_p,               # nsec, not used
+        c_char_p, c_ulonglong,  # c, clen
+        c_char_p, c_ulonglong,  # ad, adlen
+        c_char_p, c_char_p      # npub, k
+    )
+
+    # chacha20-ietf-poly1305, same api structure as above
+    libsodium.crypto_aead_chacha20poly1305_ietf_encrypt.restype = c_int
+    libsodium.crypto_aead_chacha20poly1305_ietf_encrypt.argtypes = (
+        c_void_p, c_void_p,
+        c_char_p, c_ulonglong,
+        c_char_p, c_ulonglong,
+        c_char_p,
+        c_char_p, c_char_p
+    )
+    libsodium.crypto_aead_chacha20poly1305_ietf_decrypt.restype = c_int
+    libsodium.crypto_aead_chacha20poly1305_ietf_decrypt.argtypes = (
+        c_void_p, c_void_p,
+        c_char_p,
+        c_char_p, c_ulonglong,
+        c_char_p, c_ulonglong,
+        c_char_p, c_char_p
+    )
+
+    # xchacha20-ietf-poly1305, same api structure as above
+    if hasattr(libsodium, 'crypto_aead_xchacha20poly1305_ietf_encrypt'):
+        libsodium.crypto_aead_xchacha20poly1305_ietf_encrypt.restype = c_int
+        libsodium.crypto_aead_xchacha20poly1305_ietf_encrypt.argtypes = (
+            c_void_p, c_void_p,
+            c_char_p, c_ulonglong,
+            c_char_p, c_ulonglong,
+            c_char_p,
+            c_char_p, c_char_p
+        )
+
+        libsodium.crypto_aead_xchacha20poly1305_ietf_decrypt.restype = c_int
+        libsodium.crypto_aead_xchacha20poly1305_ietf_decrypt.argtypes = (
+            c_void_p, c_void_p,
+            c_char_p,
+            c_char_p, c_ulonglong,
+            c_char_p, c_ulonglong,
+            c_char_p, c_char_p
+        )
+
+    libsodium.sodium_increment.restype = c_void_p
+    libsodium.sodium_increment.argtypes = (
+        c_void_p, c_int
+    )
+
     buf = create_string_buffer(buf_size)
     loaded = True
 
@@ -81,6 +143,10 @@ class SodiumCrypto(object):
             raise Exception('Unknown cipher')
         # byte counter, not block counter
         self.counter = 0
+        self.encrypt = self.update
+        self.decrypt = self.update
+        self.encrypt_once = self.update
+        self.decrypt_once = self.update
 
     def update(self, data):
         global buf_size, buf
@@ -103,10 +169,85 @@ class SodiumCrypto(object):
         return buf.raw[padding:padding + l]
 
 
+class SodiumAeadCrypto(AeadCryptoBase):
+    def __init__(self, cipher_name, key, iv, op):
+        if not loaded:
+            load_libsodium()
+        AeadCryptoBase.__init__(self, cipher_name, key, iv, op)
+
+        if cipher_name == 'chacha20-poly1305':
+            self.encryptor = libsodium.crypto_aead_chacha20poly1305_encrypt
+            self.decryptor = libsodium.crypto_aead_chacha20poly1305_decrypt
+        elif cipher_name == 'chacha20-ietf-poly1305':
+            self.encryptor = libsodium.\
+                crypto_aead_chacha20poly1305_ietf_encrypt
+            self.decryptor = libsodium.\
+                crypto_aead_chacha20poly1305_ietf_decrypt
+        elif cipher_name == 'xchacha20-ietf-poly1305':
+            if hasattr(libsodium,
+                       'crypto_aead_xchacha20poly1305_ietf_encrypt'):
+                self.encryptor = libsodium.\
+                    crypto_aead_xchacha20poly1305_ietf_encrypt
+                self.decryptor = libsodium.\
+                    crypto_aead_xchacha20poly1305_ietf_decrypt
+            else:
+                raise Exception('Unknown cipher')
+        else:
+            raise Exception('Unknown cipher')
+
+    def cipher_ctx_init(self):
+
+        libsodium.sodium_increment(byref(self._nonce), c_int(self._nlen))
+        # print("".join("%02x" % ord(b) for b in self._nonce))
+
+    def aead_encrypt(self, data):
+        global buf, buf_size
+        plen = len(data)
+        if buf_size < plen + self._tlen:
+            buf_size = (plen + self._tlen) * 2
+            buf = create_string_buffer(buf_size)
+        cipher_out_len = c_ulonglong(0)
+        self.encryptor(
+            byref(buf), byref(cipher_out_len),
+            c_char_p(data), c_ulonglong(plen),
+            None, c_ulonglong(0), None,
+            c_char_p(self._nonce.raw), c_char_p(self._skey)
+        )
+        if cipher_out_len.value != plen + self._tlen:
+            raise Exception("Encrypt failed")
+
+        return buf.raw[:cipher_out_len.value]
+
+    def aead_decrypt(self, data):
+        global buf, buf_size
+        clen = len(data)
+        if buf_size < clen:
+            buf_size = clen * 2
+            buf = create_string_buffer(buf_size)
+        cipher_out_len = c_ulonglong(0)
+        r = self.decryptor(
+            byref(buf), byref(cipher_out_len),
+            None,
+            c_char_p(data), c_ulonglong(clen),
+            None, c_ulonglong(0),
+            c_char_p(self._nonce.raw), c_char_p(self._skey)
+        )
+        if r != 0:
+            raise Exception("Decrypt failed")
+
+        if cipher_out_len.value != clen - self._tlen:
+            raise Exception("Encrypt failed")
+
+        return buf.raw[:cipher_out_len.value]
+
+
 ciphers = {
     'salsa20': (32, 8, SodiumCrypto),
     'chacha20': (32, 8, SodiumCrypto),
     'chacha20-ietf': (32, 12, SodiumCrypto),
+    'chacha20-poly1305': (32, 32, SodiumAeadCrypto),
+    'chacha20-ietf-poly1305': (32, 32, SodiumAeadCrypto),
+    'xchacha20-ietf-poly1305': (32, 32, SodiumAeadCrypto),
 }
 
 
@@ -133,7 +274,31 @@ def test_chacha20_ietf():
     util.run_cipher(cipher, decipher)
 
 
+def test_chacha20_poly1305():
+
+    print("Test chacha20-poly1305")
+    cipher = SodiumAeadCrypto('chacha20-poly1305',
+                              b'k' * 32, b'i' * 32, 1)
+    decipher = SodiumAeadCrypto('chacha20-poly1305',
+                                b'k' * 32, b'i' * 32, 0)
+
+    util.run_cipher(cipher, decipher)
+
+
+def test_chacha20_ietf_poly1305():
+
+    print("Test chacha20-ietf-poly1305")
+    cipher = SodiumAeadCrypto('chacha20-ietf-poly1305',
+                              b'k' * 32, b'i' * 32, 1)
+    decipher = SodiumAeadCrypto('chacha20-ietf-poly1305',
+                                b'k' * 32, b'i' * 32, 0)
+
+    util.run_cipher(cipher, decipher)
+
+
 if __name__ == '__main__':
     test_chacha20()
     test_salsa20()
     test_chacha20_ietf()
+    test_chacha20_poly1305()
+    test_chacha20_ietf_poly1305()
diff --git a/shadowsocks/crypto/table.py b/shadowsocks/crypto/table.py
index bc693f5..9e11002 100644
--- a/shadowsocks/crypto/table.py
+++ b/shadowsocks/crypto/table.py
@@ -58,6 +58,10 @@ class TableCipher(object):
     def __init__(self, cipher_name, key, iv, op):
         self._encrypt_table, self._decrypt_table = init_table(key)
         self._op = op
+        self.encrypt = self.update
+        self.decrypt = self.update
+        self.encrypt_once = self.update
+        self.decrypt_once = self.update
 
     def update(self, data):
         if self._op:
diff --git a/shadowsocks/crypto/util.py b/shadowsocks/crypto/util.py
index e579455..bb23197 100644
--- a/shadowsocks/crypto/util.py
+++ b/shadowsocks/crypto/util.py
@@ -33,7 +33,7 @@ def find_library_nt(name):
             results.append(fname)
         if fname.lower().endswith(".dll"):
             continue
-        fname = fname + ".dll"
+        fname += ".dll"
         if os.path.isfile(fname):
             results.append(fname)
     return results
@@ -92,14 +92,27 @@ def find_library(possible_lib_names, search_symbol, library_name):
     return None
 
 
+def parse_mode(cipher_nme):
+    """
+    Parse the cipher mode from cipher name
+    e.g. aes-128-gcm, the mode is gcm
+    :param cipher_nme: str cipher name, aes-128-cfb, aes-128-gcm ...
+    :return: str/None The mode, cfb, gcm ...
+    """
+    hyphen = cipher_nme.rfind('-')
+    if hyphen > 0:
+        return cipher_nme[hyphen:]
+    return None
+
+
 def run_cipher(cipher, decipher):
     from os import urandom
     import random
     import time
 
-    BLOCK_SIZE = 16384
+    block_size = 16384
     rounds = 1 * 1024
-    plain = urandom(BLOCK_SIZE * rounds)
+    plain = urandom(block_size * rounds)
 
     results = []
     pos = 0
@@ -107,18 +120,18 @@ def run_cipher(cipher, decipher):
     start = time.time()
     while pos < len(plain):
         l = random.randint(100, 32768)
-        c = cipher.update(plain[pos:pos + l])
+        c = cipher.encrypt(plain[pos:pos + l])
         results.append(c)
         pos += l
     pos = 0
     c = b''.join(results)
     results = []
-    while pos < len(plain):
+    while pos < len(c):
         l = random.randint(100, 32768)
-        results.append(decipher.update(c[pos:pos + l]))
+        results.append(decipher.decrypt(c[pos:pos + l]))
         pos += l
     end = time.time()
-    print('speed: %d bytes/s' % (BLOCK_SIZE * rounds / (end - start)))
+    print('speed: %d bytes/s' % (block_size * rounds / (end - start)))
     assert b''.join(results) == plain
 
 
diff --git a/shadowsocks/cryptor.py b/shadowsocks/cryptor.py
new file mode 100644
index 0000000..719b1b6
--- /dev/null
+++ b/shadowsocks/cryptor.py
@@ -0,0 +1,235 @@
+#!/usr/bin/env python
+#
+# Copyright 2012-2015 clowwindy
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from __future__ import absolute_import, division, print_function, \
+    with_statement
+
+import os
+import sys
+import hashlib
+import logging
+
+from shadowsocks import common
+from shadowsocks.crypto import rc4_md5, openssl, sodium, table
+
+
+CIPHER_ENC_ENCRYPTION = 1
+CIPHER_ENC_DECRYPTION = 0
+
+METHOD_INFO_KEY_LEN = 0
+METHOD_INFO_IV_LEN = 1
+METHOD_INFO_CRYPTO = 2
+
+method_supported = {}
+method_supported.update(rc4_md5.ciphers)
+method_supported.update(openssl.ciphers)
+method_supported.update(sodium.ciphers)
+method_supported.update(table.ciphers)
+
+
+def random_string(length):
+    return os.urandom(length)
+
+cached_keys = {}
+
+
+def try_cipher(key, method=None):
+    Cryptor(key, method)
+
+
+def EVP_BytesToKey(password, key_len, iv_len):
+    # equivalent to OpenSSL's EVP_BytesToKey() with count 1
+    # so that we make the same key and iv as nodejs version
+    cached_key = '%s-%d-%d' % (password, key_len, iv_len)
+    r = cached_keys.get(cached_key, None)
+    if r:
+        return r
+    m = []
+    i = 0
+    while len(b''.join(m)) < (key_len + iv_len):
+        md5 = hashlib.md5()
+        data = password
+        if i > 0:
+            data = m[i - 1] + password
+        md5.update(data)
+        m.append(md5.digest())
+        i += 1
+    ms = b''.join(m)
+    key = ms[:key_len]
+    iv = ms[key_len:key_len + iv_len]
+    cached_keys[cached_key] = (key, iv)
+    return key, iv
+
+
+class Cryptor(object):
+    def __init__(self, password, method):
+        self.password = password
+        self.key = None
+        self.method = method
+        self.iv_sent = False
+        self.cipher_iv = b''
+        self.decipher = None
+        self.decipher_iv = None
+        method = method.lower()
+        self._method_info = Cryptor.get_method_info(method)
+        if self._method_info:
+            self.cipher = self.get_cipher(
+                password, method, CIPHER_ENC_ENCRYPTION,
+                random_string(self._method_info[METHOD_INFO_IV_LEN])
+            )
+        else:
+            logging.error('method %s not supported' % method)
+            sys.exit(1)
+
+    @staticmethod
+    def get_method_info(method):
+        method = method.lower()
+        m = method_supported.get(method)
+        return m
+
+    def iv_len(self):
+        return len(self.cipher_iv)
+
+    def get_cipher(self, password, method, op, iv):
+        password = common.to_bytes(password)
+        m = self._method_info
+        if m[METHOD_INFO_KEY_LEN] > 0:
+            key, _ = EVP_BytesToKey(password,
+                                    m[METHOD_INFO_KEY_LEN],
+                                    m[METHOD_INFO_IV_LEN])
+        else:
+            # key_length == 0 indicates we should use the key directly
+            key, iv = password, b''
+        self.key = key
+        iv = iv[:m[METHOD_INFO_IV_LEN]]
+        if op == CIPHER_ENC_ENCRYPTION:
+            # this iv is for cipher not decipher
+            self.cipher_iv = iv
+        return m[METHOD_INFO_CRYPTO](method, key, iv, op)
+
+    def encrypt(self, buf):
+        if len(buf) == 0:
+            return buf
+        if self.iv_sent:
+            return self.cipher.encrypt(buf)
+        else:
+            self.iv_sent = True
+            return self.cipher_iv + self.cipher.encrypt(buf)
+
+    def decrypt(self, buf):
+        if len(buf) == 0:
+            return buf
+        if self.decipher is None:
+            decipher_iv_len = self._method_info[METHOD_INFO_IV_LEN]
+            decipher_iv = buf[:decipher_iv_len]
+            self.decipher_iv = decipher_iv
+            self.decipher = self.get_cipher(
+                self.password, self.method,
+                CIPHER_ENC_DECRYPTION,
+                iv=decipher_iv
+            )
+            buf = buf[decipher_iv_len:]
+            if len(buf) == 0:
+                return buf
+        return self.decipher.decrypt(buf)
+
+
+def gen_key_iv(password, method):
+    method = method.lower()
+    (key_len, iv_len, m) = method_supported[method]
+    if key_len > 0:
+        key, _ = EVP_BytesToKey(password, key_len, iv_len)
+    else:
+        key = password
+    iv = random_string(iv_len)
+    return key, iv, m
+
+
+def encrypt_all_m(key, iv, m, method, data):
+    result = [iv]
+    cipher = m(method, key, iv, 1)
+    result.append(cipher.encrypt_once(data))
+    return b''.join(result)
+
+
+def decrypt_all(password, method, data):
+    result = []
+    method = method.lower()
+    (key, iv, m) = gen_key_iv(password, method)
+    iv = data[:len(iv)]
+    data = data[len(iv):]
+    cipher = m(method, key, iv, CIPHER_ENC_DECRYPTION)
+    result.append(cipher.decrypt_once(data))
+    return b''.join(result), key, iv
+
+
+def encrypt_all(password, method, data):
+    result = []
+    method = method.lower()
+    (key, iv, m) = gen_key_iv(password, method)
+    result.append(iv)
+    cipher = m(method, key, iv, CIPHER_ENC_ENCRYPTION)
+    result.append(cipher.encrypt_once(data))
+    return b''.join(result)
+
+
+CIPHERS_TO_TEST = [
+    'aes-128-cfb',
+    'aes-256-cfb',
+    'rc4-md5',
+    'salsa20',
+    'chacha20',
+    'table',
+]
+
+
+def test_encryptor():
+    from os import urandom
+    plain = urandom(10240)
+    for method in CIPHERS_TO_TEST:
+        logging.warn(method)
+        encryptor = Cryptor(b'key', method)
+        decryptor = Cryptor(b'key', method)
+        cipher = encryptor.encrypt(plain)
+        plain2 = decryptor.decrypt(cipher)
+        assert plain == plain2
+
+
+def test_encrypt_all():
+    from os import urandom
+    plain = urandom(10240)
+    for method in CIPHERS_TO_TEST:
+        logging.warn(method)
+        cipher = encrypt_all(b'key', method, plain)
+        plain2, key, iv = decrypt_all(b'key', method, cipher)
+        assert plain == plain2
+
+
+def test_encrypt_all_m():
+    from os import urandom
+    plain = urandom(10240)
+    for method in CIPHERS_TO_TEST:
+        logging.warn(method)
+        key, iv, m = gen_key_iv(b'key', method)
+        cipher = encrypt_all_m(key, iv, m, method, plain)
+        plain2, key, iv = decrypt_all(b'key', method, cipher)
+        assert plain == plain2
+
+
+if __name__ == '__main__':
+    test_encrypt_all()
+    test_encryptor()
+    test_encrypt_all_m()
diff --git a/shadowsocks/encrypt.py b/shadowsocks/encrypt.py
index a86058b..ece72ec 100644
--- a/shadowsocks/encrypt.py
+++ b/shadowsocks/encrypt.py
@@ -153,7 +153,7 @@ def encrypt_all_m(key, iv, m, method, data):
     return b''.join(result)
 
 
-def decrypt_all(password, method, data):
+def dencrypt_all(password, method, data):
     result = []
     method = method.lower()
     (key_len, iv_len, m) = method_supported[method]
@@ -228,7 +228,7 @@ def test_encrypt_all_m():
         logging.warn(method)
         key, iv, m = gen_key_iv(b'key', method)
         cipher = encrypt_all_m(key, iv, m, method, plain)
-        plain2, key, iv = decrypt_all(b'key', method, cipher)
+        plain2, key, iv = dencrypt_all(b'key', method, cipher)
         assert plain == plain2
 
 
diff --git a/shadowsocks/manager.py b/shadowsocks/manager.py
index f3a7b77..55aea86 100644
--- a/shadowsocks/manager.py
+++ b/shadowsocks/manager.py
@@ -202,7 +202,7 @@ def test():
     import time
     import threading
     import struct
-    from shadowsocks import encrypt
+    from shadowsocks import cryptor
 
     logging.basicConfig(level=5,
                         format='%(asctime)s %(levelname)-8s %(message)s',
@@ -252,7 +252,7 @@ def test():
 
     # test statistics for TCP
     header = common.pack_addr(b'google.com') + struct.pack('>H', 80)
-    data = encrypt.encrypt_all(b'asdfadsfasdf', 'aes-256-cfb', 1,
+    data = cryptor.encrypt_all(b'asdfadsfasdf', 'aes-256-cfb',
                                header + b'GET /\r\n\r\n')
     tcp_cli = socket.socket()
     tcp_cli.connect(('127.0.0.1', 7001))
@@ -270,7 +270,7 @@ def test():
 
     # test statistics for UDP
     header = common.pack_addr(b'127.0.0.1') + struct.pack('>H', 80)
-    data = encrypt.encrypt_all(b'foobar2', 'aes-256-cfb', 1,
+    data = cryptor.encrypt_all(b'foobar2', 'aes-256-cfb',
                                header + b'test')
     udp_cli = socket.socket(type=socket.SOCK_DGRAM)
     udp_cli.sendto(data, ('127.0.0.1', 8382))
diff --git a/shadowsocks/shell.py b/shadowsocks/shell.py
index b46510c..ce04c1d 100644
--- a/shadowsocks/shell.py
+++ b/shadowsocks/shell.py
@@ -28,7 +28,7 @@ import traceback
 from functools import wraps
 
 from shadowsocks.common import to_bytes, to_str, IPNetwork
-from shadowsocks import encrypt
+from shadowsocks import cryptor
 
 
 VERBOSE_LEVEL = 5
@@ -200,7 +200,7 @@ def check_config(config, is_local):
     if config.get('dns_server', None) is not None:
         logging.info('Specified DNS server: %s' % config['dns_server'])
 
-    encrypt.try_cipher(config['password'], config['method'])
+    cryptor.try_cipher(config['password'], config['method'])
 
 
 def get_config(is_local):
@@ -362,6 +362,18 @@ Proxy options:
   -l LOCAL_PORT          local port, default: 1080
   -k PASSWORD            password
   -m METHOD              encryption method, default: aes-256-cfb
+                         supported method:
+                             chacha20-poly1305, chacha20-ietf-poly1305,
+                             *xchacha20-ietf-poly1305,
+                             aes-128-gcm, aes-192-gcm, aes-256-gcm,
+                             aes-128-cfb, aes-192-cfb, aes-256-cfb,
+                             es-128-ctr, aes-192-ctr, aes-256-ctr,
+                             camellia-128-cfb, camellia-192-cfb,
+                             camellia-256-cfb,
+                             salsa20, chacha20, chacha20-ietf,
+                             bf-cfb, cast5-cfb, des-cfb, idea-cfb,
+                             rc2-cfb, seed-cfb,
+                             rc4, rc4-md5, table.
   -t TIMEOUT             timeout in seconds, default: 300
   -a ONE_TIME_AUTH       one time auth
   --fast-open            use TCP_FASTOPEN, requires Linux 3.7+
@@ -392,6 +404,18 @@ Proxy options:
   -p SERVER_PORT         server port, default: 8388
   -k PASSWORD            password
   -m METHOD              encryption method, default: aes-256-cfb
+                         supported method:
+                             chacha20-poly1305, chacha20-ietf-poly1305,
+                             *xchacha20-ietf-poly1305,
+                             aes-128-gcm, aes-192-gcm, aes-256-gcm,
+                             aes-128-cfb, aes-192-cfb, aes-256-cfb,
+                             es-128-ctr, aes-192-ctr, aes-256-ctr,
+                             camellia-128-cfb, camellia-192-cfb,
+                             camellia-256-cfb,
+                             salsa20, chacha20, chacha20-ietf,
+                             bf-cfb, cast5-cfb, des-cfb, idea-cfb,
+                             rc2-cfb, seed-cfb,
+                             rc4, rc4-md5, table.
   -t TIMEOUT             timeout in seconds, default: 300
   -a ONE_TIME_AUTH       one time auth
   --fast-open            use TCP_FASTOPEN, requires Linux 3.7+
diff --git a/shadowsocks/tcprelay.py b/shadowsocks/tcprelay.py
index a61cba7..c57406d 100644
--- a/shadowsocks/tcprelay.py
+++ b/shadowsocks/tcprelay.py
@@ -26,7 +26,7 @@ import logging
 import traceback
 import random
 
-from shadowsocks import encrypt, eventloop, shell, common
+from shadowsocks import cryptor, eventloop, shell, common
 from shadowsocks.common import parse_header, onetimeauth_verify, \
     onetimeauth_gen, ONETIMEAUTH_BYTES, ONETIMEAUTH_CHUNK_BYTES, \
     ONETIMEAUTH_CHUNK_DATA_LEN, ADDRTYPE_AUTH
@@ -94,9 +94,9 @@ WAIT_STATUS_READWRITING = WAIT_STATUS_READING | WAIT_STATUS_WRITING
 
 BUF_SIZE = 32 * 1024
 
-
 # helper exceptions for TCPRelayHandler
 
+
 class BadSocksHeader(Exception):
     pass
 
@@ -125,8 +125,8 @@ class TCPRelayHandler(object):
         # if is_local, this is sslocal
         self._is_local = is_local
         self._stage = STAGE_INIT
-        self._encryptor = encrypt.Encryptor(config['password'],
-                                            config['method'])
+        self._cryptor = cryptor.Cryptor(config['password'],
+                                        config['method'])
         self._ota_enable = config.get('one_time_auth', False)
         self._ota_enable_session = self._ota_enable
         self._ota_buff_head = b''
@@ -257,7 +257,7 @@ class TCPRelayHandler(object):
             return
         if self._ota_enable_session:
             data = self._ota_chunk_data_gen(data)
-        data = self._encryptor.encrypt(data)
+        data = self._cryptor.encrypt(data)
         self._data_to_write_to_remote.append(data)
 
         if self._config['fast_open'] and not self._fastopen_connected:
@@ -347,7 +347,7 @@ class TCPRelayHandler(object):
                 offset = header_length + ONETIMEAUTH_BYTES
                 _hash = data[header_length: offset]
                 _data = data[:header_length]
-                key = self._encryptor.decipher_iv + self._encryptor.key
+                key = self._cryptor.decipher_iv + self._cryptor.key
                 if onetimeauth_verify(_hash, _data, key) is False:
                     logging.warn('one time auth fail')
                     self.destroy()
@@ -368,11 +368,11 @@ class TCPRelayHandler(object):
             # ATYP & 0x10 == 0x10, then OTA is enabled.
             if self._ota_enable_session:
                 data = common.chr(addrtype | ADDRTYPE_AUTH) + data[1:]
-                key = self._encryptor.cipher_iv + self._encryptor.key
+                key = self._cryptor.cipher_iv + self._cryptor.key
                 _header = data[:header_length]
                 sha110 = onetimeauth_gen(data, key)
                 data = _header + sha110 + data[header_length:]
-            data_to_send = self._encryptor.encrypt(data)
+            data_to_send = self._cryptor.encrypt(data)
             self._data_to_write_to_remote.append(data_to_send)
             # notice here may go into _handle_dns_resolved directly
             self._dns_resolver.resolve(self._chosen_server[0],
@@ -475,7 +475,7 @@ class TCPRelayHandler(object):
                 _hash = self._ota_buff_head[ONETIMEAUTH_CHUNK_DATA_LEN:]
                 _data = self._ota_buff_data
                 index = struct.pack('>I', self._ota_chunk_idx)
-                key = self._encryptor.decipher_iv + index
+                key = self._cryptor.decipher_iv + index
                 if onetimeauth_verify(_hash, _data, key) is False:
                     logging.warn('one time auth fail, drop chunk !')
                 else:
@@ -490,7 +490,7 @@ class TCPRelayHandler(object):
     def _ota_chunk_data_gen(self, data):
         data_len = struct.pack(">H", len(data))
         index = struct.pack('>I', self._ota_chunk_idx)
-        key = self._encryptor.cipher_iv + index
+        key = self._cryptor.cipher_iv + index
         sha110 = onetimeauth_gen(data, key)
         self._ota_chunk_idx += 1
         return data_len + sha110 + data
@@ -499,7 +499,7 @@ class TCPRelayHandler(object):
         if self._is_local:
             if self._ota_enable_session:
                 data = self._ota_chunk_data_gen(data)
-            data = self._encryptor.encrypt(data)
+            data = self._cryptor.encrypt(data)
             self._write_to_sock(data, self._remote_sock)
         else:
             if self._ota_enable_session:
@@ -564,7 +564,7 @@ class TCPRelayHandler(object):
             return
         self._update_activity(len(data))
         if not is_local:
-            data = self._encryptor.decrypt(data)
+            data = self._cryptor.decrypt(data)
             if not data:
                 return
         if self._stage == STAGE_STREAM:
@@ -598,9 +598,9 @@ class TCPRelayHandler(object):
             return
         self._update_activity(len(data))
         if self._is_local:
-            data = self._encryptor.decrypt(data)
+            data = self._cryptor.decrypt(data)
         else:
-            data = self._encryptor.encrypt(data)
+            data = self._cryptor.encrypt(data)
         try:
             self._write_to_sock(data, self._local_sock)
         except Exception as e:
diff --git a/shadowsocks/udprelay.py b/shadowsocks/udprelay.py
index 68e7c55..e966541 100644
--- a/shadowsocks/udprelay.py
+++ b/shadowsocks/udprelay.py
@@ -68,7 +68,7 @@ import struct
 import errno
 import random
 
-from shadowsocks import encrypt, eventloop, lru_cache, common, shell
+from shadowsocks import cryptor, eventloop, lru_cache, common, shell
 from shadowsocks.common import parse_header, pack_addr, onetimeauth_verify, \
     onetimeauth_gen, ONETIMEAUTH_BYTES, ADDRTYPE_AUTH
 
@@ -170,7 +170,7 @@ class UDPRelay(object):
                 else:
                     data = data[3:]
         else:
-            data, key, iv = encrypt.decrypt_all(self._password,
+            data, key, iv = cryptor.decrypt_all(self._password,
                                                 self._method,
                                                 data)
             # decrypt data
@@ -234,11 +234,11 @@ class UDPRelay(object):
             self._eventloop.add(client, eventloop.POLL_IN, self)
 
         if self._is_local:
-            key, iv, m = encrypt.gen_key_iv(self._password, self._method)
+            key, iv, m = cryptor.gen_key_iv(self._password, self._method)
             # spec https://shadowsocks.org/en/spec/one-time-auth.html
             if self._ota_enable_session:
                 data = self._ota_chunk_data_gen(key, iv, data)
-            data = encrypt.encrypt_all_m(key, iv, m, self._method, data)
+            data = cryptor.encrypt_all_m(key, iv, m, self._method, data)
             if not data:
                 return
         else:
@@ -267,13 +267,12 @@ class UDPRelay(object):
                 # drop
                 return
             data = pack_addr(r_addr[0]) + struct.pack('>H', r_addr[1]) + data
-            response = encrypt.encrypt_all(self._password, self._method, 1,
-                                           data)
+            response = cryptor.encrypt_all(self._password, self._method, data)
             if not response:
                 return
         else:
-            data = encrypt.encrypt_all(self._password, self._method, 0,
-                                       data)
+            data, key, iv = cryptor.decrypt_all(self._password,
+                                                self._method, data)
             if not data:
                 return
             header_result = parse_header(data)