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dissabte, 18 / novembre / 2006 |
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[Yahoo! News] Man tries wirelessly bossting bateries. Si això funciona, pot fer realitat l'existència de totes mena de dispositius sense fils... ja que no caldria el cable d'alimentació. De moment, però, només és teoria. Es basa en desenvolupar unes piles que puguin rebre l'alimentació a través d'un enllaç sense fils amb una font d'energia
The idea is that the recharge device and the receiver would be on the same acoustic frequency, similar to how a radio picks up only one channel at a time, so that the energy would mostly go straight to the intended battery, Soljacic said.
Some of the electromagnetic energy would go elsewhere but Sojacic doesn't believe it would harm people, noting that humans can endure strong magnetic fields with magnetic resonance imaging machines.
Soljacic envisions a device with wiring loops mounted on the ceiling of a room. He even sees this as a way of recharging electric buses on the go if there's a large "pipe" with recharging energy above a highway.
The concept of wirelessly recharging batteries has been dismissed before, deemed way too inefficient with too much energy put out into the air and little where it's supposed to go. But Soljacic said using special resonating frequencies could theoretically cut energy loss to only half of the energy produced, making the technology usable.
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11:04 (# Enllaç permanent) | Comentaris: | Trackback:
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 Publicada la versió 2.0 del GnuPG, l'aplicació estàndard per al xifrat segur del correu electrònic i dels fitxers emmagatzemats al disc dur. GnUPG es basa en la criptografia de clau pública, on cada usuari té la seva pròpia clau privada que ha de mantenir en secret i una clau pública que pot distribuir.
The GNU Privacy Guard (GnuPG) is GNU's tool for secure communication and data storage. It can be used to encrypt data, create digital signatures, help authenticating using Secure Shell and to provide a framework for public key cryptography. It includes an advanced key management facility and is compliant with the OpenPGP and S/MIME standards.
GnuPG-2 has a different architecture than GnuPG-1 (e.g. 1.4.5) in that it splits up functionality into several modules. However, both versions may be installed alongside without any conflict. In fact, the gpg version from GnuPG-1 is able to make use of the gpg-agent as included in GnuPG-2 and allows for seamless passphrase caching. The advantage of GnuPG-1 is its smaller size and the lack of dependency on other modules at run and build time. We will keep maintaining GnuPG-1 versions because they are very useful for small systems and for server based applications requiring only OpenPGP support.
El procés de xifrat es reaitza sempre utilitzant la clau privada de l'emissor i la clau pública del receptor i es garanteix que només podrà ser desxifrat per la combinació de clau privada del receptor més clau pública de l'emissor.
What's New in GnuPG-2
- The *gpg-agent* is the central place to maintain private keys and to cache passphrases. It is implemented as a daemon to be started with a user session.
- *gpgsm* is an implementation of the X.509 and CMS standards and provides the cryptographic core to implement the S/MIME protocol. The command line interface is very similar to the one of gpg. This helps adding S/MIME to application currently providing OpenPGP support.
- *scdaemon* is a daemon run by gpg-agent to access different types of smart cards using a unified interface.
- *gpg-connect-agent* is a tool to help scripts directly accessing services of gpg-agent and scdaemon.
- *gpgconf* is a tool to maintain the configuration files of all modules using a well defined API.
- Support for Dirmngr, a separate package to maintain certificate revocation lists, do OCSP requests and to run LDAP queries.
- Support for the Secure Shell Agent protocol. In fact, gpg-agent may be used as full replacement of the commonly used ssh-agent daemon.
- Smart card support for the Secure Shell.
- Documentation is now done in Texinfo. Thus besides Info, HTML and PDF versions may easily be generated.
- Man pages for all tools.
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10:55 (# Enllaç permanent) | Comentaris: | Trackback:
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 TINC és una eina per a la creació de xarxes privades virtuals totalment transparents a l'aplicació, utilitzant OpenSSL. A més a més comprimeix el tràfic amb zlib i el signa per tal d'impedir-ne la modificació. Dóna suport a IPv6 i hi ha versions per a Linux, FreeBSD, OpenBSD, NetBSD, Mac OS X, Solaris, Windows 2000 i Windows XP.
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10:44 (# Enllaç permanent) | Comentaris: | Trackback:
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© Copyright 1996-2006 Xavier Caballe.  . Si no s'indica expressament el contrari, el material publicat en aquest weblog es distribueix d'acord amb la llicència Creative Commons. El contingut és responsabilitat única i exclusivament del seu autor i no té cap relació amb les seves activitats professionals.
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