Modern and easy-to-use crypto library Formula was removed
Last versions were
php70-libsodium requires the following formulae to be installed:
autoconf 2.69 Automatic configure script builder
libsodium 1.0.16 NaCl networking and cryptography library

Recent formula history

Steven Barnett libsodium: 1.0.6
Jan Viljanen Update libsodium-php to 1.0.2 for php70
Andy Blyler regen libsodium bottles
David Guyon Bump PHP70 to RC8
David Guyon Bump PHP70 to RC7

Formula code at GitHub