Access Sequence

Index

Overview

Navigation and Tool Bars

Compare Variant

Overview top

An access sequence is presented whenever you want to log in or access a locked document. This is the 'password entry'. Depending on the parameters of the lock you will have to 'solve' a variable number of entry screens. You have to solve all screens before an attempt is made to open the associated lock.

If a sequence is solved incorrectly the access has failed, the screen will flash red and you will hear ~~this sound~~. If access is granted, the screen will flash green and you will hear ~~this sound~~.

There is a time limit placed on the entry procedure. The access sequence will fail after a given amount of time. You can cancel the sequence by tapping the

button. After 3 cancellations or 2 failures, the entry procedure will switch to fallback mode (see below).

If you realize you made a mistake on an entry screen you can go back with the

button in the navigation bar. This can only be done once per entry screen to prohibit experimentation. To allow going back after the last screen, you can choose to have the app display a Continue button. This can be switched on or off in the options screen.

Navigation and Tool Bars top

: cancel the access sequence. 3 cancellations will make the entry procedure switch to the safer fallback mode.

: tap to bring up the options screen.

: tap to go back to the previous entry screen. Works only once per screen. Since the Password variant has only a single entry screen it does not need this option.

The bottom of the entry screen displays the number of screens remaining to be solved (including the current one), and the number of seconds remaining for this access sequence. The information will turn orange, then red as you run out of time.

Compare Variant top

An entry screen for the compare variant consists of two or more groups of items. Scan all groups and look for known items. Find the group which has the most known items. The maximum number is two, even if more items are in a group.

So look at each group - if a group has two known items, this is the solution. If a group has a single known item, make a mental note and keep looking. If another group has a known item, then you know the solution must be a group with two known items - keep looking. When you have looked at all groups then tap the group with two items or the group with one item.

A special case is the coercion screen. It has two possible solutions and acts like a fork in the road. Pick the one which fits your situation. Pick either the group with two items (including the corcion item) or - the normal situation - ignore the coercion item and pick the other solution. An observer will not be able to tell which one you choose. Note: it is tempting and natural to tap on an item you recognize. Try not to do this but to tap on the group. Also, if you recognize the first group as the solution, because it has two items, still look over the other groups. This will keep an observer from deducing known items based on your response time.

In case you are forced to identify the item categories, identify the coercion item as a normal known item and, if specifically asked, insist that you are not using the coercion functionality (i.e. there is no coercion item).

Match Variant top

An entry screen for the match variant consists of a grid of items. If the grid is displayed horizontally then start at the top left and scan each column from top to bottom. If the layout is vertical then start at the top left and scan each row from left to right.

Look for the first known item. When you find one, check two more columns or rows and identify the pattern or symbol formed by the known items. Symbols are contiguous, that is, all known items are either adjacent to each other or touch at the corners. (If the lock uses the 'Wrap Symbols' option, then check both sides of the grid, the items may repeat at the edges. Find the largest contiguous group of items.)

Trace the symbol in your mind a few times. What may also help is translating the symbol into words like 'bar plus one' or 'hook'. But do everything in your mind! Then find the symbol in the symbol pad which matches the symbol formed by the known items and tap and hold it. A larger symbol will pop up. Wait until the symbol hilites, then release. You should hear ~~this sound~~. The delay is there to minimize accidental input.

Again, a special case is the coercion screen. It has two possible solutions and acts like a fork in the road. You can pick the solution you want by either including or ignoring the coercion item. This results in two different symbols. An observer will not be able to tell which one you choose.

In case you are forced to identify the item categories, identify the coercion item as a normal known item and, if specifically asked, insist that you are not using the coercion functionality (i.e. there is no coercion item).

Password Variant top

You're not really still using conventional passwords, are you? The entry screen (there is only a single one) for the password variant consists of a text entry field. Your password hint is displayed before you enter any text. Enter your normal or coercion password, then tap Continue.

If your password contains return characters, they will be entered as <CR> and later replaced with the actual return characters. In the options screen you can toggle 'Secure Password Entry' on or off to hide or show the password as you type.

Options top

Confirm after Last Screen: presents Cancel and Continue buttons after the last entry screen to give you a chance to go back to the previous screen if you made a mistake. This is for completeness's sake; for convenience you can switch this off. Since the Password variant has only a single entry screen, this option does not apply to it.

Show All Symbols at Once: applies only to the Match variant. If on, all symbols are displayed at once. This may be be a bit overwhelming and/or hard to use, especially for higher radices (up to 32). Symbols for a radix of 8 or less can be represented with 2 columns. Higher radices require 3 columns.

The alternative is to show a partial symbol pad. If a symbol can comprise 3 columns (radices 8 or greater) then the first partial symbol pad shows all possible partial symbols with 2 columns. A partial symbol has no frame and shows empty spaces. Tap on the partial symbol which best matches the desired symbol. Then tap on the next partial symbol or, if displayed, the actual symbol. There are at most three steps to reach the actual symbol. If you cannot find it, then you made a mistake along the way. Tap outside the symbol pad to reset.

: actual symbol (frame, no empty slots) with 2 columns (2 x 2) for radices 8 and below.

: actual symbol with 3 columns (3 x 2) for radices 9 to 32.

: partial symbol (no frame, empty slots) for radices 9 to 32.

Symbols on Right Side: switch the partial symbol pad to the right side.

Secure Password Entry: hide or show the password as you type.

Fallback Mode top

If you interrupt or cancel an access sequence 3 times or fail to solve it 2 times in a row, then the lock will switch to fallback mode. This means the next access will present a longer access sequence (security level >= 1 : 100,000). Once you open it successfully, it will switch again to the specified security level (which may or may not be shorter).

The fallback mode also has a longer (10 second) computational delay associated with it.

If the access sequence unsuccessfully exits 6 times, then there will be a delay screen displayed before the next access. After about 30 seconds (this delay gets longer every time) you can proceed with the access sequence. Once you pass the access sequence everything will return to normal.

These measures are meant to make any attacks by trial-and-error futile (or at the very least painful).

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