Total Commander

[DimitarSerg]

RSA ?!
Вроде для таких случаев юзают алгоритмы симметрического шифрования.

Может вот отсюда что подберешь
http://members.ozemail.com.au/~nulifetv/freezip/freeware/

напр. DSE-CLI (command-line interface)
DSE is a file encryption program.

FEATURES
- extensively tested and widely accepted AES cipher
- disclosed implementation and source code
- excellent performance and no target file size limits
- secure use of system resources
- really small executable file
- self-contained and dependency-free
- installation-and-pollution-free
- freeware status and unrestricted distribution[/url]