Conference Paper

Formalising Identity Management Protocols

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Abstract

In this paper we present the formalisation of three well-known Identity Management protocols - SAML, OpenID and OAuth. The formalisation consists of two steps: formal specification using HLPSL (High-Level Protocol Specification Language) and formal verification using a state-of-the-art verification tool for security protocols called AVISPA (Automated Validation of Internet Security Protocols and Applications). The existing formalisation initiatives using AVISPA are based on SAML and OpenID, leaving OAuth entirely, even though OAuth is one of the most widely-used Internet protocols. Furthermore, the motivation of the existing initiatives was to identify any weakness. In this paper, we have taken an opposite approach as we are keen to present how to model these protocols correctly. Moreover, our formalisation is based on a model of identity and also captures the authentication mechanism; both of these are missing in the existing works.

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... The formalize identity of the an entity e is: I e = I j e . Here, identity of entity e, denoted as I e , is the union of all partial identities (denoted as I j e ) of e. Similar to the concept of [14], Ferdous and Poet [15] represent identity as a set of partial identities and they formalize the partial identity and identity as follows: for a domain (d), the partial identity of a user (u), where u ∈ U d within d, can be denoted as, parIdent u d = {(a, v)|a ∈ A d , atEntT oV al d (a, u) is def ined and equals v}. Where, U d denotes a set of users, a is a single attribute of u, and v is the value of a. Notation atEntT oV al d is represented as a function of attribute-value pair of an entity in domain d. ...
... In specifying a formal model of IoT identity we follow the approaches discussed in [14], [15] and [26]. The model has the following components: E, A, V , Cnt, P Id and Id (sets of entity, sets of attribute, sets of attribute value, sets of context, sets of partial identity and sets of identity respectively). ...
... AVISPA is a popular security protocol verifier which uses mathematical logic to analyze the security properties of a given protocol. Researchers have used this tool to model and analyze popular security protocols such as SAML and OpenID [29,30]. In AVISPA, the security K. Hasan et al. protocols are specified using a special specification language called High-Level Protocol Specification Language (HLPSL) [31]. ...
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URI : text, KU : public_key, A : text set 22 const rs_rp_profile,rp_rs_n5,u_rp_resource,app_rp_authzresp : protocol_id 23 init 24 State
  • State
  • Uname Id
State,N5 : nat, ID,UName,URI : text, KU : public_key, A : text set 22 const rs_rp_profile,rp_rs_n5,u_rp_resource,app_rp_authzresp : protocol_id 23 init 24 State:=1 25 transition 26
AuthZResp : message)
  • Authzreq
AuthZReq,AuthZResp : message)
Security evaluation of the OpenID protocol
  • A Lindholm
Lindholm, A.. Security evaluation of the OpenID protocol. MSc. Thesis, KTH. Accessed on 1 June, 2016.
AuthZResp) 78 end role 79 80 role enviroment() 81 def= 82 const u_as_n1,u_as_n3,u_as_uname,u_as_pass,u_as_authzgrant,rs_rp_profile,rp_rs_n4,u_rp_resource, as_rs_accesstoken,as_rs_n4,rp_rs_n5,app_rp_authzresp: protocol_id
  • Rp As
  • Rs App
  • Ku
  • Krp
  • Kas
  • Kapp
  • Krs
  • Rappu Sappu
  • Rapprp Sapprp
  • Rappas Sappas
  • Rapprs Sapprs
  • Accesstoken
  • Authzgrant
  • Authzreq Profile
/\ application(U,RP,AS,APP,RS,KU,KRP,KAS,KAPP,KRS,SAPPU,RAPPU,SAPPRP,RAPPRP,SAPPAS,RAPPAS,SAPPRS,RAPPRS,AccessToken,AuthZGrant,PROFILE,AuthZReq,AuthZResp) 78 end role 79 80 role enviroment() 81 def= 82 const u_as_n1,u_as_n3,u_as_uname,u_as_pass,u_as_authzgrant,rs_rp_profile,rp_rs_n4,u_rp_resource, as_rs_accesstoken,as_rs_n4,rp_rs_n5,app_rp_authzresp: protocol_id, 83 u,as,rp,rs,app: agent, ku,kas,krp,krs,kapp,ki: public_key, resource,authzgrant,profile,accesstoken : hash_func, 84 authzreq,authzresp : message 85 intruder_knowledge={u,rp,krp,ki,inv(ki),as,kas,rs,krs,resource} 86 composition 87 session(u,as,i,app,rs,ku,kas,ki,kapp,krs,resource,authzgrant,profile,accesstoken,authzreq,authzresp) 88
Assertions and Protocols for the OASIS Security Assertion Markup Language (SAML)
  • Oasis
  • Standard
OASIS Standard. Assertions and Protocols for the OASIS Security Assertion Markup Language (SAML) V2.0. 15
The AVISPA tool for the automated validation of internet security protocols and applications
  • A Armando
  • D Basin
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  • Y Chevalier
  • L Compagna
  • J Cuéllar
  • P H Drielsma
  • P Héam
  • O Kouchnarenko
  • J Mantovani
  • Others
Armando, A., Basin, D., Boichut, Y., Chevalier, Y., Compagna, L., Cuéllar, J., Drielsma, P. H., Héam, P., Kouchnarenko, O., Mantovani, J. and others. The AVISPA tool for the automated validation of internet security protocols and applications. In International Conference on Computer Aided Verification, page 281-285, 2005.
Towards improving the usability and security of Web single sign-on systems
  • S Sun
Sun, S.. Towards improving the usability and security of Web single sign-on systems. PhD. Thesis, University of British Columbia. Accessed on 1 June, 2016. 2013. https://open.library.ubc.ca/cIRcle/collections/ ubctheses/24/items/1.0103287.
Security Usability of Petname Systems
  • M S Ferdous
  • A Jøsang
  • K Singh
  • R Borgaonkar
Ferdous, M.S., Jøsang, A., Singh, K. and Borgaonkar, R. Security Usability of Petname Systems. In NordSec'09, volume 5838 of LNCS, pages 44-59, Springer, 2009.
AccessToken) /\ secret(AccessToken,as_rs_accesstoken,{AS,RS}) /\ witness(RS,RP, rs_rp_profile,PROFILE) /\ request(RS,AS,as_rs_n4,N4') /\ witness(RS,RP,rp_rs_n5,N5') application
  • R P As
  • App Ku
  • Krp
  • Kas
  • Kapp
  • Su
  • Ru
  • Srp
  • Rrp
  • Sas
  • Ras
  • Srs
N5'}_inv(KRS).ID'}_KRP}_KAPP) /\ request(AS,RS,as_rs_accesstoken,AccessToken) /\ secret(AccessToken,as_rs_accesstoken,{AS,RS}) /\ witness(RS,RP, rs_rp_profile,PROFILE) /\ request(RS,AS,as_rs_n4,N4') /\ witness(RS,RP,rp_rs_n5,N5') application (U,RP,AS,APP,RS : agent, KU,KRP,KAS,KAPP,KRS : public_key, SU,RU,SRP,RRP,SAS,RAS,SRS,RRS : channel(dy), AccessToken,AuthZGrant,PROFILE : hash_func, → 55 AuthZReq,AuthZResp : message)
ID'}_KRP )}_inv(KAPP)}_KRP) /\ witness(APP,RP,app_rp_authzresp,AuthZResp) session (U,AS
  • Rp
  • App
  • Ku
  • Kas
  • Krp
  • Kapp
  • Resource
  • Authzgrant
  • Accesstoken Profile
State=16 /\ RRS({RS.APP.RP.{RP.{PROFILE(A').N5'}_inv(RS).ID'}_KRP}_KAPP) =|> State':=18 /\ SRP({APP.RP.{AuthZResp({RP.{PROFILE(A').N5'}_inv(KRS).ID'}_KRP )}_inv(KAPP)}_KRP) /\ witness(APP,RP,app_rp_authzresp,AuthZResp) session (U,AS,RP,APP,RS : agent, KU,KAS,KRP,KAPP,KRS : public_key, Resource,AuthZGrant,PROFILE,AccessToken : hash_func, 69