From 907243281d0e2a28f8462163a5d5e1bfc0deea95 Mon Sep 17 00:00:00 2001 From: ccremers Date: Mon, 23 May 2005 13:51:39 +0000 Subject: [PATCH] - Anti-typeflaw reordering. --- spdl/nsl-generalized-4.spdl | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/spdl/nsl-generalized-4.spdl b/spdl/nsl-generalized-4.spdl index aa10811..73c3401 100644 --- a/spdl/nsl-generalized-4.spdl +++ b/spdl/nsl-generalized-4.spdl @@ -2,7 +2,9 @@ * Generalized Needham-Schroeder-Lowe protocol. * Four-party version. * - * Vulnerable to a typeflaw attack but otherwise okay. + * Specific order of interleaving in message 1-4 is required to (a) + * avoid type flaws whilst (b) retaining NSL structure for the simple + * case. * * Mon May 23 11:49:29 CEST 2005 */ @@ -18,7 +20,7 @@ protocol nslgen4(R1,R2,R3,R4) const n1: Nonce; var n2,n3,n4: Nonce; - send_1(R1,R2, {R1,R3,R4,n1}pk(R2) ); + send_1(R1,R2, {n1,R1,R3,R4}pk(R2) ); read_4(R4,R1, {n1,n2,n3,n4,R2,R3,R4}pk(R1) ); send_5(R1,R2, {n2,n3,n4}pk(R2) ); @@ -36,8 +38,8 @@ protocol nslgen4(R1,R2,R3,R4) const n2: Nonce; var n1,n3,n4: Nonce; - read_1(R1,R2, {R1,R3,R4,n1}pk(R2) ); - send_2(R2,R3, {n1,n2,R1,R2,R4}pk(R3) ); + read_1(R1,R2, {n1,R1,R3,R4}pk(R2) ); + send_2(R2,R3, {n1,R1,n2,R2,R4}pk(R3) ); read_5(R1,R2, {n2,n3,n4}pk(R2) ); send_6(R2,R3, {n3,n4}pk(R3) ); @@ -55,8 +57,8 @@ protocol nslgen4(R1,R2,R3,R4) const n3: Nonce; var n1,n2,n4: Nonce; - read_2(R2,R3, {n1,n2,R1,R2,R4}pk(R3) ); - send_3(R3,R4, {n1,n2,n3,R1,R2,R3}pk(R4) ); + read_2(R2,R3, {n1,R1,n2,R2,R4}pk(R3) ); + send_3(R3,R4, {n1,R1,n2,R2,n3,R3}pk(R4) ); read_6(R2,R3, {n3,n4}pk(R3) ); send_7(R3,R4, {n4}pk(R4) ); @@ -74,7 +76,7 @@ protocol nslgen4(R1,R2,R3,R4) const n4: Nonce; var n1,n2,n3: Nonce; - read_3(R3,R4, {n1,n2,n3,R1,R2,R3}pk(R4) ); + read_3(R3,R4, {n1,R1,n2,R2,n3,R3}pk(R4) ); send_4(R4,R1, {n1,n2,n3,n4,R2,R3,R4}pk(R1) ); read_7(R3,R4, {n4}pk(R4) );