For linux there's LUKS and the windows analogon would be
FreeOTFEBut it seems the author has disappeared and the development has stalled (some might say the project has been abandoned) but it works at least on windows and linux.
Seems there's a fork of this called
DoxBox Another fork of TrueCrypt called
CipherShedanother that is called
veracryptSome further crossplatform alternatives:
TruPax which is compatible to TrueCrypt volumes and implemented in Java
EncFS which can also be used for DropBox
tcplay which seems to be a TrueCrypt implementation from an archlinux contributor
zulucrypt which is a frontend for dmcrypt and tcplay and allows to e.g. easily open LUKS and TrueCrypt volumes
securstick which only seems to be for USB flash drives
https://www.aescrypt.com/DiskCryptor does not seem to offer a linux version
eCrypFS does not seem to offer a windows version
Some time ago there was
CrossCrypt but this seems dead and gone.
For more see e.g.
http://softwarerecs.stackexchange.com/q ... -truecryptFWIW, for truecrypt the complete source code was published, so feel free to take a look at e.g.
https://www.grc.com/misc/truecrypt/truecrypt.htmhttp://istruecryptauditedyet.com/https://opencryptoaudit.org/reports/iSe ... ssment.pdfhttps://madiba.encs.concordia.ca/~x_dec ... -analysis/