I2P is an anonymous network exposing a simple layer that applications can use to anonymously and securely send messages to each other. The network itself is strictly message based (ala IP), but there is a library available to allow reliable streaming communication on top of it (ala TCP). All communication is end to end encrypted (in total there are four layers of encryption used when sending a message), and even the end points ("destinations") are cryptographic identifiers (essentially a pair of public keys).

Changelog:
- Several bug fixes and improvements to the plugin support introduced in 0.7.12
- Fix a bug with window size adjustment that had a big impact on outbound bandwidth
- Fix a bug with handling duplicate SYN packets
- Rework several parts of the UDP transport to eliminate locking
- Lower the number of duplicate acks included in UDP to reduce protocol overhead
- Greatly reduce global locking in the bandwidth limiter
- Fix a bug that caused bandwidth burst limits to stay high when the bandwidth limits were reduced via the console
- Enable the new, smaller tunnel build message, to reduce bandwidth and improve build success
- Fix a bug causing routers with high clock skew to drop messages
- Adjust the floodfill peer rankings to speed up leaseset lookups
- Increase the number of floodfills again
- Improvements to reduce the bandwidth in tracker communications
- Fix a bug preventing successful startup when the router.keys file was missing
- Enable pack200 in the installer to shrink the install file by 3MB
- Speed up hostname lookups
- Reduce job queue global locking
- More changes for performance

Program Information Category: Tools and Utilities Type: Free Version: 0.7.13 Size: 5.3MB Works on: Windows Product page: here