John the Ripper is a fast password cracker, currently available for many flavors of Unix, Windows, DOS, BeOS, and OpenVMS. Its primary purpose is to detect weak Unix passwords. It supports several crypt(3) password hash types commonly found on Unix systems, as well as Windows LM hashes. On top of this, lots of other hashes and ciphers are added in the community-enhanced version (-jumbo), and some are added in John the Ripper Pro.
Open Transactions is a solid, easy-to-use, financial crypto and digital cash library, including an API, server, and test client. It features anonymous numbered accounts, untraceable digital cash, triple-signed receipts, basket currencies, and signed XML contracts. It also supports cheques, invoices, payment plans, markets with trades, and other instruments. It uses OpenSSL and Lucre blinded tokens.
pdfcrypt allows you to set permissions on a PDF file. For example, you can publish a document without permitting users to print it. The button to print the file will be disabled in the Acrobat Reader application. It can be used as a batch application to set permissions on a large group of PDF files, or as a filter in a Unix pipeline, or within a CGI application. Only binary executables are distributed, but the original Perl source code may be requested.