Download
sigwrite-1.2.0.zip (111K) 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.
Here is the md5 checksum for the download, signed with Gryphel Key 5:
--------- GRY SIGNED TEXT --------- 88431b1a988637870f706027db02cbf4 sigwrite-1.2.0.zip ------- BEGIN GRY SIGNATURE ------- Gry/4Xa8CFcUzxdN/Oj+k7MxmYKs7dr4k5oFxKGZTyzmGkgonzXfMUQv+CJbAI9i 0bTxRjTKDrYI2M6jpTkkUFlBr2yIK1sf0ot5w6swikh1SB9mHrn4xB6ziYFjfdNz YZlrucKZnfznk87kVEuWiMQz7v+xltMEIHKa5cy+9UH0VOcimAfT46lFmZFQMDoX -------- END GRY SIGNATURE --------
See the Compiling page for instructions on compiling SigWrite from the source code.
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If you find SigWrite useful, please consider helping the Gryphel Project, of which it is a part.
