You can get my usual gpg public key here:

 http://www.mat.puc-rio.br/~nicolau/sucuri.key

The following gpg public key is intended for more critical use:

 http://www.mat.puc-rio.br/~nicolau/boto.key

I also have a pgp public key, but please prefer the gpg key above:

 http://www.mat.puc-rio.br/~nicolau/old.key

In case you want to use gpg or pgp but are not familiar with it, follow the links below:

 http://www.gnupg.org

 http://www.pgp.com