Add support for encryption -- using mcrypt or gpg where applicable

Packages describing “crypt” as local USE flag

Package“crypt” Flag Description
app-crypt/libsecretEnable transport encryption
app-editors/gvimUse dev-libs/libsodium for crypto support
app-editors/vimUse dev-libs/libsodium for crypto support
app-forensics/volatility3support plugins that decrypt passwords, password hashes, etc.
dev-libs/libgdataUse app-crypt/gcr for keeping tokens and passwords in non-pageable memory for improved security
dev-libs/totem-pl-parserSupport AmazonAMZ decoding with dev-libs/libgcrypt
kde-apps/okularEnable support for password-encrypted documents via kde-frameworks/kwallet
kde-plasma/plasma-metaPull in kde-plasma/plasma-vault for encrypted vaults integration
net-analyzer/nscaBuild support for crypted communication with nsca, through dev-libs/libmcrypt. It's recommended not to disable this flag unless all the communication will be handled in an absolutely safe environment.
net-im/gajimEnd to end encryption and GPG encryption
net-irc/limnoriaEnables user authentication with GPG
net-irc/quasselSupport core->network per-channel and per-query blowfish encryption via app-crypt/qca SLOT 2.
net-mail/notmuchSupport decryption and verification of PGP/MIME messages and in Emacs UI - encryption; support also S/MIME signature verification since version 0.22
sci-geosciences/owntracks-recorderEnable support for payload encryption with dev-libs/libsodium
sys-libs/glibcbuild and install libcrypt and crypt.h
sys-power/suspendAllows suspend and resume from encrypted disk

All packages providing a “crypt” USE flag (41)