Illustration by Jørgen Stamp digitalbevaring.dk CC BY 2.5 Denmark
Introduction
This section is intended as guidance for practitioners at a novice or intermediate level on the implications of information security for digital preservation. Information Security issues relate to system security (e.g., protecting digital preservation and networked systems / services from exposure to external / internal threats); collection security (e.g., protecting content from loss or change, the authorisation and audit of repository processes); and the legal and regulatory aspects (e.g. personal or confidential information in the digital material, secure access, redaction). Information security is a complex and important topic for information systems generally. It is important to rely on relevant expertise within your organisation and beyond it through government and other networks for general information security procedures and advice. You may also need appropriate advocacy for specific digital preservation procedures and requirements.
Rigorous security procedures will:
- Ensure compliance with any legal and regulatory requirements;
- Protect digital materials from inadvertent or deliberate changes;
- Provide an audit trail to satisfy accountability requirements;
- Act as a deterrent to potential internal security breaches;
- Protect the authenticity of digital materials;
- Safeguard against theft or loss.
Many types of digital material selected for long-term preservation may contain confidential and sensitive information that must be protected to ensure they are not accessed by non-authorised users. In many cases these may be legal or regulatory obligations on the organisation. These materials must be managed in accordance with the organisation's Information Security Policy to protect against security breaches. ISO 27001 describes the manner in which security procedures can be codified and monitored (ISO, 2013a). ISO 27002 provides guidelines on the implementation of ISO 27001-compliant security procedures (ISO, 2013b). Conforming organisations can be externally accredited and validated. In some cases your own organisation's Information Security Policy may also impact on digital preservation activities and you may need to enlist the support of your Information Governance and ICT teams to facilitate your processes.
Information security methods such as encryption add to the complexity of the preservation process and should be avoided if possible for archival copies. Other security approaches may therefore need to be more rigorously applied for sensitive unencrypted files; these might include restricting access to locked-down terminals in controlled locations (secure rooms), or strong user authentication requirements for remote access. However, these alternative approaches may not always be sufficient or feasible. Encryption may also be present on files that are received on ingest from a depositor, so it is important to be aware of information security options such as encryption, the management of encryption keys, and their implications for digital preservation.
Techniques for protecting information
Several information security techniques may be applied to protect digital material:
Encryption
Encryption is a cryptographic technique which protects digital material by converting it into a scrambled form. Encryption may be applied at many levels, from a single file to an entire disk. Many encryption algorithms exist, each of which scramble information in a different way. These require the use of a key to unscramble the data and convert it back to its original form. The strength of the encryption method is influenced by the key size. For example, 256-bit encryption will be more secure than 128-bit encryption.
It should be noted that encryption is only effective when a third party does not have access to the encryption key in use. A user who has entered the password for an encrypted drive and left their machine powered on and unattended will provide third parties with an opportunity to access data held in the encrypted area, which may result in its release.
Similarly encryption security measures (if used) can lose their effectiveness over time in a repository: there is effectively an arms race between encryption techniques and computational methods to break them. Hence, if used, all encryption by a repository must be actively managed and updated over time to remain secure.
Encrypted digital material can only be accessed over time in a repository if the organisation manages its keys. The loss or destruction of these keys will result in data becoming inaccessible.
Access Control
Access controls allow an administrator to specify who is allowed to access digital material and the type of access that is permitted (for example read only, write). The Handbook follows the National Digital Stewardship Alliance (NDSA) preservation levels in recommending four levels at which digital preservation can be supported through access control. The NDSA levels focus primarily on understanding who has access to content, who can perform what actions on that content and enforcing these access restrictions (NDSA, 2013) as follows:
NDSA level |
Activity |
1 |
|
2 |
|
3 |
|
4 |
|
Redaction
Redaction refers to the process of analysing a digital resource, identifying confidential or sensitive information, and removing or replacing it. Common techniques applied include anonymisation and pseudonymisation to remove personally identifiable information, as well as cleaning of authorship information. When related to datasets this is usually carried out by the removal of information while retaining the structure of the record in the version being released. You should always carry out redaction on a copy of the original, never on the original itself.
The majority of digital materials created using office systems, such as Microsoft Office, are stored in proprietary, binary-encoded formats. Binary formats may contain significant information which is not displayed, and its presence may therefore not be apparent. They may incorporate change histories, audit trails, or embedded metadata, by means of which deleted information can be recovered or simple redaction processes otherwise circumvented. Digital materials may be redacted through a combination of information deletion and conversion to a different format. Certain formats, such as plain ASCII text files, contain displayable information only. Conversion to this format will therefore eliminate any information that may be hidden in non-displayable portions of a bit stream.
Resources
ENISA. 2013, Cloud Security Incident Reporting
The EU's Agency for Network & Information Security offers recommendations on the ways in which cloud providers and their customers should respond to – and report – security breaches. (38 pages).
ISO 27001:2013, Information technology— Security techniques — Information security management systems — Requirements. Geneva: International Organization for Standardization
http://www.iso.org/iso/catalogue_detail?csnumber=54534
ISO 27001 describes the manner in which security procedures can be codified and monitored. Conforming organisations can be externally accredited and validated. A template for a set of policies aligned with the standard is available. Note that these are headings, to assist with policy creation, rather than policy statements. However, similar policy sets are in use in a substantial number of organisations. (23 pages).
ISO 27002:2013, Information technology – Security techniques – Code of practice for information security controls. Geneva: International Organization for Standardization
http://www.iso.org/iso/catalogue_detail?csnumber=54533
ISO 27002 provides guidelines on the implementation of ISO 27001-compliant security procedures. (80 pages)
ISO 27799:2008, Health informatics – Information security management in health using ISO/IEC 27002. Geneva: International Organization for Standardization
http://www.iso.org/iso/catalogue_detail?csnumber=41298
ISO 27799 provides specific advice on implementing ISO 27002 and 27001 in the healthcare sector. (58 pages)
Cabinet Office, 2009, HMG IA Standard No. 1 – Technical Risk Assessment
https://www.ncsc.gov.uk/guidance/information-risk-management-hmg-ia-standard-numbers-1-2
A detailed discussion and standard intended for UK Risk Managers and Information Assurance Practitioners who are responsible for identifying, assessing and treating the technical risks to systems and services that handle, store and process digital government information. (114 pages).
Redaction toolkit (TNA 2011)
http://www.nationalarchives.gov.uk/documents/information-management/redaction_toolkit.pdf
This TNA toolkit was produced in 2011 to provide guidance on editing exempt material from information held by public bodies. It covers generic principles records in any media but has a small section specifically on electronic records and detailed guidance on methods for securely redacting electronic records of all types. (21 pages).
BitCurator
BitCurator is a suite of open source digital forensics and data analysis tools to help collecting institutions holding born-digital materials. Parts of the toolset help locate private and sensitive information on digital media and prepare materials for public access.
Information Commissioners Office (ICO): Information security
The ICO website has guidance on reporting of security breaches and use of IT. For those working in organisations falling under the ICO's jurisdiction an understanding of what this guidance recommends is essential to starting conversations with ICT and Information Governance Colleagues as they will need to be assured that work can be carried out in compliance with ICO recommendations.
Access to the Secure Lab
https://www.ukdataservice.ac.uk/get-data/how-to-access/accesssecurelab
A number of confidential and sensitive microdata sources are becoming available through datalabs across the UK. These data are deemed potentially identifiable, and can only be accessed through a datalab facility (as opposed to download). In addition, researchers are asked to fullfil a number of additional application requirements. Some of these data may be accessed via the Secure Lab of the UK Data Service and this page provides useful overviews and access to relevant user agreements.
Case studies
Opening access to administrative data for evaluating public services: The case of the Justice Data Lab
http://evi.sagepub.com/content/21/2/232.full.pdf+html
The Justice Data Lab a unit within a secure setting holding evaluation and statistical expertise has enabled providers of programmes aimed at reducing re-offending to obtain evidence on how the impact of their interventions differs from that of a matched comparison group. This article explores the development of the Justice Data Lab, the methodological and other challenges faced, and the experiences of user organizations. The article draws out implications for future development of Data Labs and the use of administrative data for the evaluation of public services. (16 pages).
UK Data Service: Data Security
https://www.ukdataservice.ac.uk/manage-data/store/security
This webpage summarises how the UK Data Archive manages data security for its holdings. Data security may be needed to protect intellectual property rights, commercial interests, or to keep sensitive information safe. Arrangements need to be proportionate to the nature of the data and the risks involved. Attention to security is also needed when data are to be destroyed.
References
NDSA, 2013. The NDSA Levels of Digital Preservation: An Explanation and Uses, version 1 (2013). Available: http://www.digitalpreservation.gov/ndsa/working_groups/documents/NDSA_Levels_Archiving_2013.pdf
ISO, 2013a. ISO 27001:2013 - Information technology - Security techniques - Information security management systems - Requirements. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/catalogue_detail?csnumber=54534
ISO, 2013b. ISO 27002:2013 - Information technology – Security techniques – Code of practice for information security controls. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/catalogue_detail?csnumber=54533
Comments