Secrecy is the act of keeping information hidden from people who do not need to know it, while sharing it with others. The information that is kept hidden is called a secret.

Secrecy can be a topic of debate, depending on what the secret is, who is keeping it, and why it is being kept.

When governments keep secrets, it is sometimes criticized as being too much or as harming how well they operate. Sharing too much information about people can go against the values of privacy and keeping personal information safe. Secrecy is often compared to the idea of being open and honest with others.

Secrecy can happen in different ways:
– Encoding or encryption, which uses math and technology to hide messages.
– True secrecy, where rules are set to prevent people from learning about a message, such as through government security levels.
– Obfuscation, where secrets are hidden in plain sight using difficult or unusual language or methods like steganography.

Another way to classify secrecy was proposed by Claude Shannon in 1948. He said there are three systems of secrecy within communication.

Sociology

Animals hide where they live to stay safe from predators. Squirrels bury nuts and try to remember where they hid them later.

People sometimes hide parts of themselves because of feelings like shame or fear of being hurt, rejected, or losing their jobs. People may also hide parts of themselves that they cannot accept or understand. Families sometimes keep "family secrets," meaning they agree not to talk about certain topics with others or even within the family. Families may use a shared story to explain these secrets when talking to outsiders. Agreement to keep secrets is sometimes forced through shame or by talking about family honor. Some secrets are about simple things, like a recipe.

Secrets are sometimes kept to create surprises, such as hiding plans for a surprise party, avoiding spoilers in a story, or keeping a magic trick secret.

Keeping strategies secret is important in many games.

In anthropology, sharing secrets helps people form traditional connections with others. This idea is shown in Joseph Conrad's short story "The Secret Sharer."

Government

Governments sometimes try to hide information from other governments and the public. These secrets may include plans for weapons, military strategies, methods used in diplomatic talks, and information obtained without permission ("intelligence"). Most countries have laws, such as the Official Secrets Act (or the Espionage Act in the United States), that classify information based on how much protection it needs ("classified information"). People who need to access this information must have a security clearance, and other measures, like storing documents in secure places, are required.

Most people agree that keeping information about nuclear weapons secret is important, but many think governments keep too many secrets and use them for political reasons. Some countries have laws that try to reduce government secrecy, such as the U.S. Freedom of Information Act and sunshine laws. Sometimes, government workers share information they are not allowed to reveal. An example from 2005 is the Plame affair.

Keeping information secret during elections is becoming a bigger concern, especially when computer systems are used to count votes. When people vote, they act in a special role as the people who choose their leaders (not as subjects of the law, as they are outside of elections). Some argue that secrecy is not allowed in elections, where the government gains its power and the right to collect taxes. However, how much secrecy is allowed depends on the situation.

Corporations

Many organizations, including large companies and charities, keep secrets for different reasons. These reasons include gaining an advantage over competitors, following laws, or hiding illegal actions. Examples of secret information include new products being created, special ways of making goods, or lists of customers. Laws about trade secrets help protect this kind of information.

Studies about corporate secrecy look at why some groups keep information hidden. Researchers in economics and management have studied how companies in groups called cartels work together to stay secret and avoid being caught by officials who check for unfair business practices. The variety of companies in these groups, such as their size and age, affects how well they can work together to stay hidden.

The patent system helps inventors by letting them share their ideas in exchange for a short period of time when they can use the invention without competition. However, patent applications are not public at first. Secret societies use secrecy to attract members by making them feel special or important.

Shell companies can be used for illegal activities like hiding money from crimes, funding terrorism, or avoiding taxes. Lists that show who truly owns a company are created to help reduce corporate secrecy.

Other laws require organizations to keep certain information private. For example, medical records in the United States must be kept secret under HIPAA. Financial reports that are not yet finished must also stay private to prevent unfair advantages in the stock market. In Europe, there are strict rules to protect the privacy of information stored in databases.

Computing

Keeping secrets safe is an important goal in information security. Methods used to achieve this include physical security and cryptography. Cryptography relies on keeping special keys secret. Some people think that security systems work better when their details are not hidden.

Information hiding is a key idea in software engineering. It is easier to check if software works correctly when different parts of the program can only use a limited amount of known information.

Military

Military secrecy means keeping information about military matters hidden from the public and enemies. This is done to gain an advantage, hide weaknesses, avoid embarrassment, or support propaganda. Most military secrets are about tactics, such as the strengths and weaknesses of weapons, training methods, plans, and the number and location of weapons. Some secrets are about bigger topics, like secret communications, code-making, intelligence work, and working with other groups.

The rights of the US government about military secrecy were supported in an important court case called United States v. Reynolds, decided by the Supreme Court in 1953.

Views

Too much secrecy is often a cause of many conflicts between people. Keeping a secret might require lying, which can cause mental problems. Another choice is not answering a question, but this might hint at the answer and isn't always a good way to keep a secret. Also, the other person might insist on getting an answer.

About 2500 years ago, Sophocles wrote: "Do not do things secretly because Time sees and hears everything and will reveal everything." Gautama Siddhartha said: "Three things cannot stay hidden for long: the sun, the moon, and the truth."