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In cryptography, the Tiny Encryption Algorithm (TEA) is a block cipher notable for its simplicity of description and implementation (typically a few lines of code). The cipher's designers were David Wheeler and Roger Needham of the Cambridge Computer Laboratory, and the algorithm was first presented at the Fast Software Encryption workshop in 1994 (Wheeler and Needham, 1994). It is not subject to any patents.

TEA operates on 64-bit blocks and uses a 128-bit key. It has a Feistel structure with a suggested 64 rounds, typically implemented in pairs termed cycles. It has an extremely simple key schedule, mixing all of the key material in exactly the same way for each cycle. Different multiples of a magic constantIn computer programming, a magic number is a special constant used for some specific purpose. It is called magic because its value or presence is inexplicable without some additional knowledge. Magic numbers are often chosen based on (among others): ASCII are used to prevent simple attacks based on the symmetrySymmetry is a characteristic of geometrical shapes, equations and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. The three main symmetri of the rounds.

TEA has a few weaknesses. Most notably, it suffers from equivalent keys — each key is equivalent to three others, and this means that the effective key size is only 126 bitThis article is about the unit of information, see Bit (disambiguation) for other meanings. A bit (abbreviated b is the most basic information unit used in computing and information theory. A single bit (short for b inary dig it is a zero or a one, or a ts (Kelsey et. al., 1996). This weakness led to a method for hackingHacker is a term used to describe different types of computer experts. It is also sometimes extended to mean any kind of expert, especially with the connotation of having particularly detailed knowledge or of cleverly circumventing limits. The meaning of MicrosoftMicrosoft Corporation , headquartered in Redmond, Washington, USA, is the world's largest software company (with over 50,000 employees in various countries, as of May 2004). Microsoft develops, manufactures, licenses and supports a wide range of software's XboxThe Xbox is Microsoft's game console, released on November 15 2001. It is Microsoft's first independent venture into the console arena, after having collaborated with Sega in porting Windows CE to the Sega Dreamcast console. The price is currently 149 USD game console, where the cipher was used as a hash function. TEA is also susceptible to a related-key attack which requires 2²³ chosen plaintexts under a related-key pair, with 2³² time complexity (Kelsey et. al., 1997).

Because of these weaknesses, a number of revisions of TEA have been designed, including XTEA.