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the Gryphel Project


The goal of the Gryphel Project is to help preserve software made for early Macintosh computers, the computers that Apple sold from 1984 to 1996 based upon Motorola’s 680x0 microprocessors.

Mini vMac

The center of this project - a family of free and open source emulators that allow such software to be used on modern computers

More

The rest of this project - software for the early Macintosh, links to alternatives to Mini vMac, links to related forums, lists of books, and more.

Latest News : February 18, 2018

GSgWrite is a new tool for writing digital signatures that is very similar to SigWrite, except that it uses a different signature format. SigCheck has been updated to handle this new format. (Also SigWrite has been updated to include recent improvements in the text editing window code from SigCheck.)

The main difference in GSgWrite from SigWrite is that when a message containing a public key, or even a nested signed message, is signed with GSgWrite, the signed message contains the exact same text without modification. The PGP format created by SigWrite is designed to be read in one pass from beginning to end, so some kinds of text could cause confusion and have to be modified. The “GRY” format created by GSgWrite is designed to be scanned backwards from the end to find the end of the message body.

This makes the GRY format incompatible with the PGP format. And since it is incompatible anyway, some further changes were made.

First, the GRY format is a bit more compact. For a 1024 bit key, the body of the GRY signature is always exactly 3 lines of 64 characters each. Second, the GRY format format attempts to mitigate known weaknesses in the md5 checksum by including a second md5 checksum, of the same data with the bytes in reverse order. Even if someone finds a practical way to generate a file with a given md5 checksum, finding a file that also has the second checksum right is likely to be more difficult. (The size of the signature depends on the size of the key, not on the size of the digest. A larger digest is fine as long as it is smaller than the key.) Also, CRC-24 checksums for both orders are included in the digest, since code for CRC-24 is already there (used for protecting the signature body against accidental corruption).

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Thanks to Justin Williams, Rienk Koolstra, Marcin Rusinowski, Leo E Tognella, Jonathan Heiman, and Grafico Freelancer for sponsoring about one month of web hosting for the Gryphel project and 6 days of health insurance.

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