Safeguarding Data With WORM: Technologies, Processes, Legalities And Standards

The Illusion of Security

When most of us think about safeguarding computer-generated data, we think in terms of technology. Which technology will best protect the data? Which technology will prevent accidental loss and intentional tampering? Which technology can ensure data will be accessible and readable whenever it's needed?

Based on those questions, a great number of companies worldwide have settled on the optical Write-Once-Read-Many (WORM) technology as the ideal storage solution. WORM addresses their needs perfectly from a technological point of view. Yet unless those same companies ask a few more questions, they have achieved only the illusion of data security.

They should also be asking, "What really keeps data safe? Is it recording technology, or the way the technology is implemented? Is it the recording medium? The method of recording data? The way data is handled after it's recorded?"

According to rulings by U.S. courts and by the Securities and Exchange Commission, it's all of the above.

Consider that, in a U.S. court of law, evidence is considered admissible or inadmissible based on how it is handled, not on the medium or technology that stores the evidence. Paper, audiotape, videotape, photographs, even hand-written records have been accepted into evidence, even though these media can be altered, some very easily. The reason is simple. If courts could accept only evidence that is recorded on "inviolate" media, they would have literally no hard evidence at all since every storage medium in existence can be altered. Optical storage and other computer-based technologies are no exception.

The key, then, is more about process (the way we handle data) and less about technology (the way we record data). True, technology is critical to data security, and some technologies are inherently more stable than others. For example, a WORM disk is much harder to alter than a signature. But, in fact, both are vulnerable to someone with sufficient access, the right tools, and adequate knowledge. As described in this white paper, technology is just part of the answer. If your in-house process controls break down, no technology in the world can protect your data.

Process Controls

In managing and safeguarding computer-based information, companies worldwide must implement the two fundamental requirements for data security:
  • System Integrity, and
  • System Security
System integrity must be addressed at all levels of hardware and software that comprise the computer system. Errors that occur, whether human or system-generated, could propagate to a rewritable storage media. WORM storage technology prevents these errors from corrupting data that has been properly recorded to an optical WORM disk. This is where WORM realizes its greatest benefit.

On the other hand, system security is the process and physical barriers that ensure only authorized personnel are allowed access to critical system areas. People with malicious intentions can find many ways to alter records. For example, they can remove a WORM disk, record a new one and insert it in the system with the altered data. Note that the type of WORM technology used is irrelevant. What is more important is who has a password to the system and who has keys to the doors.

Some specific actions that can be taken to strengthen the security of a system include:
  1. Physical access to optical WORM disks must be restricted. The disks should be stored in a secure place, preferably under lock and key.
  2. Access to the operating system and optical drivers must be limited to a trusted system administrator.
  3. Sufficient system securities must be in place so users cannot easily circumvent the built-in safeguards. The ideal in-house process includes additional safeguards to deter, prevent, or detect unauthorized modification of data.
With these controls in place, data on WORM media is permanent, secure and invulnerable to accidental or intentional tampering. But if any one of these in-house process controls is absent, data is at risk regardless of the technology.

Today's WORM Technologies

WORM offers long-term storage strategy that virtually eliminates accidental erasure of data. To understand just how stable the technology is, consider these descriptions of today's most common WORM recording formats:

Ablative WORM uses a laser to burn pits in the recording surface of an optical disk.

Continuous Composite Write-once (CCW WORM) uses a laser and magnet to alter magnetic flux directions in the recording surface of an optical disk.

Bubble forming and Dye-polymer WORM use a laser to form small bubbles on the recording surface of an optical disk.

Phase-change WORM uses a laser to change the molecular structure of a disk's recording surface from an amorphous to crystalline state.

Alloy-forming WORM uses a laser to form a metal alloy on the disk itself.

None of these technologies is inherently more alterable than the others. In all cases, the write process depends on the extreme heat of a laser to momentarily raise the temperature of a disk's recording surface by hundreds of degrees centigrade. With all WORM products, the disk is changed in some way during writes; during reads, a laser detects those changes.

The real protection of data comes from the WORM drives themselves, all of which provide the following safeguards:
  • Disk identification. The drives look for codes that are physically stamped into disks at time of production, which tell it to enable only WORM commands.
  • Written sector detection. When the drives see a sector with previously written data, writing is disallowed to prevent data from being overwritten or corrupted.
  • Defect management. If a drive discovers a corrupt data sector on optical disk, the drive can automatically "spare out" the bad sector, flag it as corrupt, and disallow future writes and reads to that sector.
With these safeguards, WORM drives provide virtual fail-safe protection against accidental erasure of data. However, no optical technology is safe against malicious tampering since even the best security measures of optical drives can be defeated.

Built-In Technology Safeguards

How hard is it to compromise data on optical disks? If your in-house process controls break down, it's difficult at best, but still possible if the following conditions are met:
  1. Malicious intent plus in-depth technical knowledge. A technical specialist must have a deep understanding of the inner workings of optical technology, operating systems, and optical drive firmware.
  2. Access to the operating system and device drivers. Assuming a high degree of technical knowledge, a specialist who has unrestricted access to the deepest levels of the operating system and optical drivers can cause a lot of damage, though not without detection.
  3. Access to optical disks and drive firmware. Someone with unrestricted access to optical disks and drive firmware can – assuming thorough technical knowledge, ample opportunity and high incentive — alter data on WORM media.
While it is theoretically possible to alter any type of WORM media, the degree of difficulty required to subvert the technology is far greater than the effort required to subvert process controls. There are no known cases to date of WORM data alteration.

Legal Precedents

Due to the effort required to compromise WORM data and the inherent stability of optical disks, the U.S. Commodities Future Trading Commission announced in 1993 that optical disks were an acceptable storage medium for the Commission's required computer-generated records. The CFTC further clarified its ruling the following year by stating that CCW WORM media, as approved in the ISO standard, is a form of WORM media and is therefore acceptable.

In June 1993, the U.S. Securities and Exchange Commission (SEC) proposed that broker-dealers be allowed to preserve records using optical storage technology as long as the technology:
  1. Preserves records in a non-rewritable, non-erasable format;
  2. Verifies automatically the quality and accuracy of the optical storage recording process;
  3. Duplicates in a separate optical disk all information originally preserved and maintained by means of optical storage technology;
  4. Serializes original and duplicate optical disks containing records, and time-dates permanently the information placed on such optical disks; and
  5. Has the capacity to download indexes and records preserved on optical disks into paper, microfilm or microfiche
In Apri1 1997, the SEC amended its 1993 ruling to expand the electronic storage options available to broker-dealers. It allows them to use any WORM storage media, no matter the underlying technology, as long as it meets the conditions set forth in the final ruling. Magneto-optical is specifically called out in the ruling as acceptable.

The Issue Of Industry Standards

WORM recording technology considerations being equal, any evaluation of a WORM solution must also consider industry standards; primarily to assure continued accessibility of data over the long-term.

Of all WORM types, only CCW WORM has been standardized by ANSI, ISO and ECMA. Today, multiple suppliers are selling CCW WORM drives and media, whereas other types of WORM products are generally single-sourced and proprietary.

Also, since CCW WORM development is controlled by industry standards, all CCW WORM products are backward compatible. Today's 5.2 GB drives can still read disks created on the earliest 650 MB CCW WORM drives.

Conclusions
  • No technology or storage medium is tamper-proof, whether optical, tape, magnetic disk, paper or film.
  • Data security depends on both process controls and technology.
  • All WORM technologies are equally reliable and inherently safe.
  • All WORM technologies provide overwrite prevention and blank checking functions that prevent accidental erasure of data.
  • Once written, WORM disks are extremely difficult to alter.
  • WORM disks are stable, offering an archival life of at least 25 years.
  • The SEC and the CFTC accept WORM technologies.
  • CCW WORM is the only write-once technology governed by industry standards and served by multiple vendors who compete equally in the marketplace.