www.gryphel.com/c/minivmac/extras/sigwrite - feedback

## SigWrite

#### a Mini vMac Extra

Download

> sigwrite-1.2.0.zip (info) a zipped hfs disk image and checksum file. The disk image can be mounted with Mini vMac. Includes source code.

SigWrite is a tool for creating digital signatures that can be checked with the SigCheck tool. Public and secret key pairs for these tools can be created with MakeKeys.

To use SigWrite, launch the application, and in the editing window that appears, paste in a message to be signed. For example:

>     Twas brillig, and the slithy toves
>     did gyre and gimble in the wabe:
>     All mimsy were the borogoves,
>     and the mome raths outgrabe.

Copy all of the indented text above. Then paste it into SigWrite, which requires getting the clipboard into the emulated Macintosh, if SigWrite is run inside Mini vMac. You can get text into the emulated Macintosh using the “Host Paste” command in the Edit Menu of SigWrite. It is like the “Paste” command, except that it uses the clipboard of the real computer instead of the clipboard of the emulated computer. The keyboard shortcut is Command-Option-V. (The “Host Paste” command has similar effect to using ClipIn and then the normal “Paste” command.)

Then click on the status bar, at the bottom of the window below the editing area. (Choosing the ‘Go’ command from the File menu, of the emulated Macintosh, will also work. The keyboard shortcut is Command-G.)

The editing area is cleared. Next paste in a secret key to sign the message with. (One can be created with MakeKeys). For example (and only as example, normally a secret key should never be given to anyone else):

>     ----- BEGIN GRY SECRET KEY -----
>     Gry+SKAIAAA/AXuKqWsF8Rh5Ie4/vORBnTxYf8FPpRl/n6hpgDgfJ5MAOsAEyePE
>     nSfjmL3I9emNTuW/iCIHlCl/WkaWyMQZ+NDb1ZsnSLyOKwOycVkR3JwJbUamM4wy
>     jUuoWV6jzuhqWZobpGPMSN4B3ivHXtcNVm5SVmnAL13T4FCLnx+TxaYRAQAB9n9N
>     yEapaUzZs3Pdv2zNzs77wWHev2/i0qAIFxBLWI5VvPd6NuXEefADAtAJHhzm9koz
>     gWrLZ9pVF+D537ewv3/mZJPGS0u7Ino5F3AQ20NhDvX3JwovUSgUkmy59PbJgZ2M
>     0zNCvKuephFJbT4Pgi2oc7ZT/qZagkNNDErbyLb7NvBAU6+Ezbb2ejBd0C7s5tM4
>     Eu8DD8MJUOdZXctnyzF4F0Nz+TG+NtqN/0Ks8OGUCRysWLyciQ6iej7+vivHhLxr
>     wPBA26XYQmRphwlwz6n+VNzd9huh29Ak12ZwgeNpkyO1LIdueVUu6f+sUJYx1Hlg
>     tkHwE6ax3jPN+5osKOQ8/0Pg3fY/8CwOIpqLB6QDLCtY2ZrfM69mWkw/QTyGNSDU
>     FIkI5corJbgms5mGMGQ2CyEZZ3RjzDtP5YwVAdzd4oNdKLHsK+k4nA==
>     ------ END GRY SECRET KEY ------

Before continuing, it would be a good idea to set Mini vMac to All Out speed. Then, on a modern computer, SigWrite should take less than ten seconds to run (for a 1024 bit key, as in this example). At 1x speed, or on a real Macintosh Plus, it takes much longer. The code of SigWrite is intended to be simple to understand and maintain, as opposed to fast.

Again, click on the status bar. After a while, if all is well, the edit area is replaced with the signed text:

>     --------- GRY SIGNED TEXT ---------

>     Twas brillig, and the slithy toves
>     did gyre and gimble in the wabe:
>     All mimsy were the borogoves,
>     and the mome raths outgrabe.

>     ------- BEGIN GRY SIGNATURE -------
>     Gry/AXuKqWsF8Rh5/Bb045yIowANlvp/V/ymKoDa55Wb7dW/xGfPmca8oLw+Rv9d
>     cSQpcL+XpzESnWqpK/uNg7lTIe4wdOzo1/s6bHU0u27J+A5EngkYQiAMHeETq6Nx
>     DM8viQbkNx2UZrDxyOLCGXW1N4txMktyjC3DYzRMH/oKBVHxgP6B2j8sipEgp3Zf
>     -------- END GRY SIGNATURE --------

When SigWrite is run inside Mini vMac, you can get text out of the emulated Macintosh using the “Host Copy” command in the Edit Menu. It is like the “Copy” command, except that it uses the clipboard of the real computer instead of the clipboard of the emulated computer. The keyboard shortcut is Command-Option-C. (The “Host Copy” command has similar effect to using the normal “Copy” command and then ClipOut.)

SigWrite is in part descended from MacPGP source code, which, as far as I can tell, allows derived works for noncommercial use.

MacPGP has various code to try to protect secrets from other software running on the computer. SigWrite does not, instead you should try to secure the entire virtual machine that it is run in. Such as by putting the Mini vMac disk image on an encrypted volume of the host computer, for a start.

If a file named “sec_key.txt” exists in the same folder as the application, then SigWrite will not ask for the secret key, but instead get it from that file. So you can save time for a frequently used key by setting up a copy of SigWrite this way. You can save even more time by “wrapping” this copy of SigWrite with AutoQuit.

SigWrtTl is a command line version of SigWrite.

SigWrite is a successor to PSgWrite, which uses a different format that is more or less compatible with MacPGP.

See the Compiling page for instructions on compiling SigWrite from the source code.

:

If you find SigWrite useful, please consider helping the Gryphel Project, of which it is a part.

www.gryphel.com/c/minivmac/extras/sigwrite - feedback
copyright (c) 2018 Paul C. Pratt - last update 10/19/2018