Termit
Library for serializing Erlang terms to signed encrypted binaries and reliably deserializing them back.
Usage
A typical use case is to provide means to keep secrets put in public domain, e.g. secure cookies.
% generate a token
Term = {this, is, an, [erlang, <<"term">>]}.
Cookie = termit:encode_base64(Term, <<"cekpet">>).
% token is ok
{ok, Term} = termit:decode_base64(Cookie, <<"cekpet">>).
% check whether token is not forged
{error, forged} = termit:decode_base64(<<Cookie/binary, "1">>, <<"cekpet">>).
{error, forged} = termit:decode_base64(Cookie, <<"secret">>).
{error, forged} = termit:decode_base64(undefined, <<"cekpet">>).
% generate expiring token
Term = {this, is, another, [erlang, <<"term">>]}.
% time-to-live is 10 seconds =:= secret valid no more than 10 seconds
Cookie = termit:encode_base64(termit:expiring(Term, 10), <<"cekpet">>).
% secret is ok within 10 seconds interval
{ok, Decoded} = termit:decode_base64(Cookie, <<"cekpet">>).
{ok, Term} = termit:check_expired(Decoded).
% after 10 seconds elapsed
{ok, Decoded} = termit:decode_base64(Cookie, <<"cekpet">>).
{error, expired} = termit:check_expired(Decoded).
% shortcuts for expiring security tokens, e.g. OAuth2 bearer tokens
Token = termit:issue_token([{user, <<"dvv">>}, {scope, <<"admin.*">>}], <<"ThanksBob!">>, 24 * 60 * 60).
{ok, Data} = termit:verify_token(Token, <<"ThanksBob!">>).
{error, forged} = termit:verify_token(Token, <<"ThanksBob?">>).
% generate non expiring token
Term = {a, b, c, [d, "e", <<"foo">>]},
Secret = <<"TopSecRet">>,
Token = termit:issue_token(Term, Secret),
{ok, Term} = verify_token(Token, Secret).Thanks
Bob Ippolito for invaluable assistance in improving the library usability.
License
Copyright (c) 2013 Vladimir Dronnikov dronnikov@gmail.com
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
