[Teep] OTrP Signature Security issue

Anders Rundgren <anders.rundgren.net@gmail.com> Tue, 20 November 2018 20:57 UTC

From: Anders Rundgren <anders.rundgren.net@gmail.com>
To: "teep@ietf.org" <teep@ietf.org>
Message-ID: <c47a641d-3931-dc0e-100a-f6fa1a8e0593@gmail.com>
Date: Tue, 20 Nov 2018 21:57:08 +0100
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Archived-At: <https://mailarchive.ietf.org/arch/msg/teep/0y_vjaSHqB1EUHGyIEyBoOqVlUk>
Subject: [Teep] OTrP Signature Security issue
Precedence: list

The following is a for brevity simplified version of the OTrP signature scheme.  That OTrP rather uses the JSON serialized version of JWS has no security advantages (or disadvantages) over the JWS compact notation shown here:
{
    "carObject":  "eyetc.eyetc.xyxetc"
}

Since "carObject" isn't signed, you can replace it with anything else and the signature will still validate.


Using detached JWS combined with JCS [1,2] you sign the entire JSON object as well as getting the "payload" in clear:
{
    "carObject": {
       "brand":  "Ferrari",
       "horsePower":  "450",
       "weight":  "2357kg"
    },
    "signature": "eyetc..xyect"
}

thanx,
Anders

1] https://tools.ietf.org/html/draft-rundgren-json-canonicalization-scheme-01
2] https://mobilepki.org/jws-jcs

[Teep] OTrP Signature Security issue Anders Rundgren
Re: [Teep] OTrP Signature Security issue Hannes Tschofenig
Re: [Teep] OTrP Signature Security issue Anders Rundgren
Re: [Teep] OTrP Signature Security issue Anders Rundgren
Re: [Teep] OTrP Signature Security issue Carsten Bormann
Re: [Teep] OTrP Signature Security issue Anders Rundgren
Re: [Teep] OTrP Signature Security issue Hannes Tschofenig
Re: [Teep] OTrP Signature Security issue Anders Rundgren
Re: [Teep] OTrP Signature Security issue Hannes Tschofenig
Re: [Teep] OTrP Signature Security issue Anders Rundgren