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).
CACKey provides a standard interface (PKCS#11) for smartcards connected to a PC/SC compliant reader. It performs a similar function to "CoolKey", but only supports Government Smartcards. It supports all Government Smartcards that implement the Government Smartcard Interoperability Specification (GSC-IS) v2.1 or newer.
sphlib provides optimized implementations in both C and Java of cryptographic hash functions. The C code includes "small footprint" variants optimized for architectures with low L1 cache (e.g. WiFi routers running OpenWRT). The C code comes with a command-line tool that can serve as a drop-in replacement for md5sum, sha1sum, sha256sum, etc. for all implemented hash functions. The Java code is compatible with J2ME. There are implementations of fourteen "second-round" SHA-3 candidates, for all output lengths: BLAKE, Blue Midnight Wish, CubeHash, ECHO, Fugue, Grøstl, Hamsi, JH, Keccak, Luffa, Shabal, SHAvite-3, SIMD, and Skein. Some pre-SHA-3 hash functions (including MD4, MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, RIPEMD-160, and others) are also implemented.
Bitcoin is a peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending.
Industria is a collection of portable R6RS Scheme libraries for cryptography (AES, DES, Blowfish, HMAC, MD5, SHA-1, SHA-2, RSA, DSA, etc.), zip/gzip/zlib decompression, disassembly of amd64 machine code, Off-The-Record messaging, bytevector pack/unpack syntax, TLS connections via custom binary ports, and more.
The Open-Transactions project is a collaborative effort to develop a robust, commercial-grade, fully-featured, free-software toolkit implementing a full-strength financial cryptography library, API, CLI, and prototype server. Open-Transactions democratizes financial and monetary actions. You can use it for issuing currencies/stock, paying dividends, creating asset accounts, sending/receiving digital cash, writing/depositing cheques, cashier's cheques, creating basket currencies, trading on markets, scripting custom agreements, recurring payments, escrow, etc. Strong crypto is used. Balances are unchangeable (even by a malicious server). Receipts are destructible and redundant. The transactions are unforgeable. The cash is untraceable. The cheques are non-repudiable.