PyCryptoPlus is a cryptographic module similar to PyCrypto, with which it shares the API. But PyCryptoPlus is written 100% in Python, so its primary interest is educational and scientific; if you want real speed, you're better checking out PyCrypto. It was not completely written from scratch, but integrates other cipher codes when available in Python and under appropriate licenses. It contains, among other things: Block cipher algorithms (Serpent, Blowfish, Twofish, DES, 3DES, AES, Rijndael, and PRESENT); modes of operation (CMAC, ECB, CBC, CTR, and XTS); paddings (bit padding, zeros, PKCS7, PKCS12, ISO 10126, and ANSI X.923); and one-way functions (MD5, SHA1/SHA2, Whirlpool, RipeMD, RadioGatun, HMAC, and PBKDF2).
Tomb is a system to make strong encryption easy for everyday use. A tomb is like a locked folder that can be safely transported and hidden in a filesystem. Its keys can be kept separate; for example, you can keep the tomb on your computer and its key on a USB stick. Tomb is written in code that is easy to review and links shared components: it consists of a ZShell script and desktop integration apps; it uses standard GNU tools and the cryptographic API of the Linux kernel (dm-crypt) via cryptsetup.
pgmp is a PostgreSQL extension module that adds support for the arbitrary precision data types offered by the GMP library. It provides higher performance arithmetic for numbers, only limited by the 1GB varlena maximum size, a rational data type for absolute precision storage and arithmetic, and specialized functions to deal with prime numbers, random numbers, and factorization. The GMP data types can be used in mixed arithmetic with other PostgreSQL numeric types and indexed using the btree or hash methods. The extension is compatible with PostgreSQL 8.4 and later, and the package includes comprehensive documentation and regression tests.