Stream Cipher

What Does Stream Cipher Mean?

A stream cipher is a method of encryption where a pseudorandom cipher digit stream is combined with plain text digits. This pseudorandom cipher digit stream is applied to each binary digit, one bit at a time. This method of encryption uses an infinite number of pseudorandom cipher digits per key.


Stream cipher is also known as state cipher.

Techopedia Explains Stream Cipher

A stream cipher encrypts an arbitrary length of plain text, one bit at a time, with an algorithm that uses a key. For this form of encryption to remain secure, its psuedorandom cipher digits should be unpredictable and the key should never be used more than once. The pseudorandom cipher digits are generated through a number of random seed values that use digital shift registers. The encryption of each digit is dependent on the current state of the cipher, warranting the name state cipher for this. RC4 is a popular stream cipher that is widely used in software.


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Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.