diff --git a/shadowsocks/crypto/openssl.py b/shadowsocks/crypto/openssl.py
index 45e152e..7bce8b3 100644
--- a/shadowsocks/crypto/openssl.py
+++ b/shadowsocks/crypto/openssl.py
@@ -23,7 +23,7 @@ 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
+    EVP_CTRL_AEAD_GET_TAG, EVP_CTRL_AEAD_SET_TAG
 
 __all__ = ['ciphers']
 
diff --git a/shadowsocks/crypto/sodium.py b/shadowsocks/crypto/sodium.py
index 75ea83a..69196a3 100644
--- a/shadowsocks/crypto/sodium.py
+++ b/shadowsocks/crypto/sodium.py
@@ -287,7 +287,7 @@ ciphers = {
 
 
 def test_salsa20():
-    
+
     print("Test salsa20")
     cipher = SodiumCrypto('salsa20', b'k' * 32, b'i' * 16, 1)
     decipher = SodiumCrypto('salsa20', b'k' * 32, b'i' * 16, 0)
@@ -398,4 +398,3 @@ if __name__ == '__main__':
     test_chacha20_ietf_poly1305_chunk()
     test_aes_256_gcm()
     test_aes_256_gcm_chunk()
-