CertiGuide to Security+  9  Chapter 3:  Infrastructure Security (Domain 3.0; 20%)       9  3.2  Media            9  3.2.4  Removable Media

3.2.4.1  Tape 1 2 3.2.4.3  Hard Drives

Security Issues with CD-R

How long will a CD-R or CD-RW last? This is a matter for some debate, due to the claims now being made for some types of discs, such as 75 years for cyanine dye, 100 years for phthalocyanine dye on gold discs or even 200 years for phthalocyanine dye on “platinum” discs. Unrecorded (blank) discs are estimated to have a shelf life of 5-10 years.

On the care and keeping of CD-R’s and CD-RWs, CD-R FAQ recommends, “keep them in a cool, dark, dry place and they will probably live longer than you do,” because aside from scratching, the main enemies of CD-R’s are heat, humidity and direct sunlight (CDs, not being magnetic media, are not sensitive to magnetic fields)³¹⁴.

Along these lines, what if you have CD-Rs or CD-RWs containing proprietary data, which you want to render unreadable before disposing of? Again, the CD-R FAQ has suggestions, such as scraping off the reflective layer with something sharp (warning: this may still leave data on the dye residue), running the disc through a sander, etc. Although not a mil-spec procedure for rendering all data on a CD unreadable, a combination of scratching the surface and breaking the CD into pieces seems to be popular. Since data is redundantly written to multiple locations on a CD, if you do this, make sure you’ve done more than make a few token scratches on the media.

3.2.4.1  Tape 1 2 3.2.4.3  Hard Drives