erlang的token值加解密

对于加解密，需客户端和服务器制定好对应的规则（如：加密算法（aes，des等）、加密模式（cbc，cfb）)，去加密，再按逆序列解密。这里的key是根据数字、大小写字母、符合组合的，每次请求获取一个动态key，暂且叫做”一次一密钥“；

而也可以设计为：前后端一开始定义好一个固定key，这样好处是：就不需获取随机key，也不需要在最后把加密内容和Key穿插起来发送，只需给需加密的内容加密即可。

但这样的坏处是：如果拿到固定的key，就可以模拟前端报文连续给server端发消息，key的级别不强；而每次随机获取key相对就好了很多。

下面附erlang做客户端加密部分代码及服务端解密部分代码：

 -module(cc).

 -compile(export_all).

 -define(TOKEN_IVEC, <<"Egl63xPQYEcIY0RJ">>).

 %%client加密部分
 aes_encode() ->
    Time = list_to_binary(integer_to_list(unixtime1()) ++"000" ),
    io:format("Time...client...~p~n",[Time]),
    Key  = list_to_binary(random()),
    io:format("Key...client...~p~n",[Key]),
    AES = crypto:aes_cbc_128_encrypt(Key, ?TOKEN_IVEC, Time),
    Text = base64:encode(AES),
    Text1 = binary_to_list(Text),
    End =  foldl(lists:sublist(Text1,1,16),binary_to_list(Key)) ++ lists:sublist(Text1,17,8),
    End.

 %随机生成16位Key值
  random() ->
   Str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_",
   %%一次随机取多个，再分别取出对应值
   N = [random:uniform(length(Str)) || _Elem <- lists:seq(1,16)],
   RandomKey = [lists:nth(X,Str) || X<- N ],
   RandomKey.     

 unixtime1() ->
     {MegaSecs, Secs, _MicroSecs} = erlang:now(),
     MegaSecs * 1000000000 + Secs * 100000 .

 foldl(A, B) ->
     foldl(A, B, []).
 foldl([H|T], [H1|T1], Acc) ->
     foldl(T, T1, Acc++[H|[H1]]);
 foldl([], [], Acc) ->
     Acc.

 %%server解密部分
 verify_token( Token ) ->
     case Token of
         "" ->
             {error, "token error"};
         TokenStr ->
             {CryptoStr, Key} = verify_token_scan(TokenStr, <<>>, <<>>, 16),
   io:format("Key...server...~p~n",[Key]),
             Cipher = base64:decode(CryptoStr),
             TimestampStr = binary_to_list(crypto:aes_cbc_128_decrypt(Key, ?TOKEN_IVEC, Cipher)),
             Timestamp = list_to_integer(lists:sublist(TimestampStr, 13)),

 io:format("Timestamp ...server...~p~n",[Timestamp]),
             Now = now_time(),
             if
                 Timestamp > (Now - 691200) * 1000 ->
                     ok;
                 true ->
                     {error, "1token error"}
             end
     end.

 now_time() ->
      {X, Y, _} = now(),
      X * 1000000 + Y.    

 verify_token_scan(TokenStr, CryptoStr, Key, 0) ->
     {iolist_to_binary([CryptoStr, TokenStr]), Key};
 verify_token_scan([C, K|TokenStr], CryptoStr, Key, KeyLength) ->
     verify_token_scan(TokenStr, <<CryptoStr/binary, C>>, <<Key/binary, K>>, KeyLength - 1);
 verify_token_scan([], CryptoStr, Key, _KeyLength) ->
     {CryptoStr, Key}.

运行结果如下：

涉及了随机数的取法，加解密及base64转码以及反序列化的解密等东西.