Multilevel security: reprise

Multilevel security is the prevention of unauthorized disclosure among multiple information classes. The threat source for the disclosures includes unauthorized users and subverted software operating on behalf of authorized users. The terminology might be more explicit if we could call this concept multidomain confidentiality, but it is worth resisting multiplying terminology. Nonetheless, we should understand that multilevel security means multidomain confidentiality. The author asks if there is less need for multilevel security today, and if there is still a need, how we might address it.     

Defending cyberspace

Professionals for Cyber Defense (PCD) recommends that President Bush promptly initiates a scientific process to assess the scale and gravity of the strategic threat of cyber warfare against the US. We expect it will confirm repeated warnings from the technical community. Assuming that such a process affirms a serious national threat, we urge the federal government to: assume a strong defensive role against serious attack; focus on countering strategic attacks having real-world effects; develop a top-down architecture and engineered approach to the problem; acknowledge that current technology is insufficient to defend against cyber warfare; and subsidize critical private defenses. We believe these recommendations must ultimately lead to an aggressive program involving the commitment of both private and public resources.     

A Possible Path to Prebiotic Peptides Involving Silica and Hydroxy Acid‐Mediated Amide Bond Formation

The formation of alanine and glycine oligomers in films produced by drying aqueous mixtures of lactic acid and silica nanoparticles has been studied as a model prebiotic reaction. The addition of silica results in alanine or glycine enrichment in the polymers. Oligomerization proceeds through ester‐mediated peptide bond formation in an acidic and evaporative environment at temperatures as low as 85 °C. For both amino acids, the dominant species produced in the presence of silica and lactic acid are rich in amide bonds and deficient in ester linkages. At higher temperatures, glycine and alanine oligomers contain only a single hydroxy acid residue conjugated to the peptide N terminus. Similar product distributions occur with silica particles prereacted with lactic acid, which suggests the catalytic role of a functionalized surface. This work highlights the role minerals might have served in transitioning from oligomers with both ester and amide linkages (depsipeptides) to peptides in a prebiotic context.