From acd9a5d32f22afc10a807ffdc4da5ccb6ce87fcf Mon Sep 17 00:00:00 2001 From: Hubert Chathi Date: Mon, 20 Aug 2018 19:35:27 -0400 Subject: [PATCH] add note about Bob mashing the "Verify" button prematurely --- proposals/1543-qr_code_key_verification.md | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/proposals/1543-qr_code_key_verification.md b/proposals/1543-qr_code_key_verification.md index 0256cafbb..8388d27f7 100644 --- a/proposals/1543-qr_code_key_verification.md +++ b/proposals/1543-qr_code_key_verification.md @@ -83,6 +83,21 @@ Step 4 is to ensure that Bob does not present a QR code claiming to be Carol's key. Without this check, Bob will be able to trick Alice into verifying a key under his control, and evesdropping on Alice's communications with Carol. +The security of verifying Alice's key depends on Bob not hitting the "Verified" +button until after Alice's device indicates success. However, users have a +tendency to click on buttons without reading what the screen says. This might +be addressed by: + +- allowing Bob to easily undo the verification if Alice's device subsequently + gives an error +- posing Bob a dummy question that he cannot answer until after Alice's device + displays the check results. For example: "Does Alice's device show a cat or + a dog?" Alice's device will show one or the other after it has checked the + key received from Bob, forcing Bob to wait for the check to complete. + (Whether a cat or a dog is displayed could be keyed to, for example, a bit in + the transaction ID.) +- (possibly other ways) + Other Issues ------------