# dpkg -l | grep 'gnutls\|nettle'
ii  libcurl3-gnutls:amd64                     7.26.0-1+wheezy13             amd64        easy-to-use client-side URL transfer library (GnuTLS flavour)
ii  libcurl4-gnutls-dev                       7.26.0-1+wheezy13             amd64        development files and documentation for libcurl (GnuTLS flavour)
ii  libgnutls-dev                             2.12.20-8+deb7u3              amd64        GNU TLS library - development files
ii  libgnutls-openssl27:amd64                 2.12.20-8+deb7u3              amd64        GNU TLS library - OpenSSL wrapper
ii  libgnutls26:amd64                         2.12.20-8+deb7u3              amd64        GNU TLS library - runtime library
ii  libgnutlsxx27:amd64                       2.12.20-8+deb7u3              amd64        GNU TLS library - C++ runtime library
ii  libnettle4:amd64                          2.4-3                         amd64        low level cryptographic library (symmetric and one-way cryptos)