1  ## Table of Contents
 2  - [Closed-Source Intelligence](#closed-Source-Intelligence-(CSINT))
 3  - [In historical context for CSINT](#in-historical-context-for-CSINT)
 4  - [References](#references)
 5  - back to [main guide](../README.md)
 6    
 7  ## Closed-Source Intelligence (CSINT)
 8  
 9  CSINT[^1][^2] refers to "Closed-Source Intelligence." It is the process of collecting and analyzing information from non-public, restricted, or confidential sources. These sources can include classified government documents, proprietary corporate data, internal communications, or data obtained through confidential agreements or intelligence networks. CSINT is used in investigations where sensitive or confidential information is critical, such as in law enforcement, intelligence organizations, corporate security, and private investigations.
10  
11  CSINT access is typically regulated legally, requiring court orders, warrants, or special permissions, and it involves a structured process of accessing, collecting, and analyzing this restricted information safely and ethically. It provides insights that are often unavailable through public or open sources, making it valuable in cases like criminal investigations, national security, and corporate fraud. Its use is bound by strict legal and ethical considerations to protect privacy and avoid misuse.
12  
13  > "Information sources are categorized as open, closed, and classified. Open source (OSINT) includes publicly available materials like reports, theses, and newsletters, but may be unreliable or biased. Closed source information is restricted data in databases containing personal records or intelligence, with limited access. Classified information, gathered through covert human or technical intelligence, is highly accurate but has strict dissemination controls that can limit practical use" (United Nations, 2011, p. 12).[^2]
14  > 
15  > "Closed source data, because of its origin, is often considered more accurate and reliable" (Pennsylvania State University, n.d.)[^1].
16  > 
17  > "Throughout history, military, religious and community leaders have actively sought individuals with information-gathering skills, basing decisions on intelligence obtained this way. The earliest recognized text on this subject is 'The Art of War, The Art of Strategy' by Sun Tzu, a 5th century BC Chinese warlord and mercenary. He was acclaimed for commanding successful military operations through effective intelligence gathering and decision-making. This work remains essential reading for military and corporate strategists and intelligence operatives worldwide, demonstrating that deploying information gatherers for military operations is commonplace" (United Nations, 2011, p. 3).[^2]
18  
19  ## In historical context for CSINT:
20  
21  > "All warfare is based on deception" and "As a result, only an enlightened ruler and a wise general will use the army's highest intelligence for spying purposes, achieving great success. Spies are a critical element in water (warfare) because they determine an army's ability to move."(Sun-Tzu 3-62)[^3]
22  
23  Meaning that [HUMINT](HUMINT.md) is also CSINT, both historically and in the modern world.
24  
25  In summary:
26  - CSINT involves collecting confidential, non-public information through methods that may be legal (with proper authority) or illegal (such as hacking), depending on the context.
27  - CSINT may derive from human sources, such as interrogations, interviews, or insider reporting. This includes both government and civilian contexts—for example, corporate due diligence, employee vetting, or business negotiations.
28  - HUMINT and CSINT overlap, but can be separate; it again all depends on the context. Was it a secret operation or an interview? Was this from a closed source document?
29  
30  See [HUMINT](HUMINT.md) and [Breached Data](../README.md#breached-data) for related examples. Analysts should be cautious: while closed sources are often more reliable, they are not immune to rumor or bias. As the CIA notes, restricted information 
31  
32  >“typically involves confidential personnel decisions, upcoming policy announcements relevant to staff, or compelling rumors” (CIA para. 22)[^4].  
33  
34  Rumors can undermine or compromise the credibility of a human source, a risk particularly relevant when HUMINT and CSINT intersect.
35  
36  ## References:
37  
38  [^1]: Pennsylvania State University, et al. (n.d.). *L3.09: Closed Source Data.* www.e-education.psu.edu/geointmooc/node/2016
39  
40  [^2]: United Nations. (2011). *Criminal intelligence: Manual for analysts*. United Nations Office on Drugs and Crime. https://www.unodc.org/documents/organized-crime/Law-Enforcement/Criminal_Intelligence_for_Analysts.pdf
41  
42  [^3]: 孫子, and Lionel Giles. Sun-Tzu on the Art of War: The Oldest Military Treatise in the World. 1910. Leicester, United Kingdom, United Kingdom of Great Britain and Northern Ireland, Allandale Online Publishing, 2000, sites.ualberta.ca/~enoch/Readings/The_Art_Of_War.pdf.
43  
44  [^4]: Sunzi. The Art of Strategy: A New Translation of Sun Tzu’s Classic The Art of War. 1988.
45  
46  [^5]: CIA. *How to Sound Like a Spy: Five Colloquialisms at CIA* 19 Sept. 2024, www.cia.gov/stories/story/how-to-sound-like-a-spy-five-colloquialisms-at-cia.