Description: The Galois/Counter Mode (GCM) is a mode of operation for block ciphers that combines the encryption functionality of the counter mode (CTR) with data authentication provided by the Galois mode. This approach allows not only efficient data encryption but also ensures its integrity and authenticity. In GCM mode, data is encrypted in blocks using a counter that increments for each block, allowing for parallel processing and high encryption speed. At the same time, a Galois field-based authentication algorithm is used to generate an authentication tag that verifies that the data has not been altered during transmission. This combination of encryption and authentication is especially valuable in applications where data security is critical, such as secure communications and storage of sensitive information. GCM mode is widely used in security protocols like TLS (Transport Layer Security) and IPsec, where both confidentiality and integrity of transmitted data are required.
History: The Galois/Counter Mode was proposed in 2007 by David A. McGrew and John Viega as part of an effort to improve the security and efficiency of encryption modes of operation. Its design is based on the use of Galois fields for authentication, allowing for fast and efficient verification of data integrity. Since its introduction, GCM has been adopted in various security standards, including the Advanced Encryption Standard (AES) and has been widely used in secure networking and storage applications.
Uses: Galois/Counter Mode is primarily used in applications where both encryption and data authentication are required. It is commonly found in security protocols like TLS and IPsec, which are fundamental for online communication security. It is also used in secure storage systems and in protecting sensitive data in enterprise and government environments.
Examples: An example of Galois/Counter Mode usage is in the implementation of HTTPS, where it is used to encrypt communication between web browsers and servers. Another example is in cloud data storage, where it ensures that stored files are encrypted and authenticated to protect user privacy.
