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Message forgery

Message sent with a fake identity

Wikipedia contributorsAdapted for Fathomly · View authors
1 min read
Source updated June 13, 2026

In cryptography, message forgery is sending a message so to deceive the recipient about the actual sender's identity. A common example is sending a spam or prank e-mail as if it were originated from an address other than the one which was really used.

01Notable Incidents

2014 Sony Pictures hack

In November 2014, the multinational entertainment studio, Sony Pictures, suffered a huge data leak; over 100 terabytes of confidential company activities were exposed, resulting in well over $100 million lost.

One of the causes of the hack was through the use of message forgery. The phishers gained entry by manipulating the recipient to open the malicious attachments contained in the emails that were posing as colleagues of the top-level employees within the company.

Watch videos about Message forgeryExplainers and documentaries on YouTube (opens in a new tab)

Sources and credits

This article is adapted from the Wikipedia article “Message forgery”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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Related topics

Phishing

Phishing is a form of social engineering and a scam where attackers deceive people into revealing sensitive information or installing malware such as viruses, worms, adware, or ransomware. Phishing attacks have become increasingly sophisticated and often transparently mirror the site being targeted, allowing the attacker to observe everything while the victim navigates the site, and traverses any additional security boundaries.

Message authentication code

In cryptography, a message authentication code, sometimes known as an authentication tag, is a short piece of information used for authenticating and integrity-checking a message. In other words, it is used to confirm that the message came from the stated sender (its authenticity) and has not been changed (its integrity).

Stream cipher attacks

Stream ciphers, where plaintext bits are combined with a cipher bit stream by an exclusive-or operation, can be secure if used properly. However, they are vulnerable to attacks if certain precautions are not followed: Keys must never be reused.