Secret key cryptography was traditionally divided into block ciphers and stream ciphers, but over the last 30 years the balance had steadily shifted, and today stream ciphers have become an endangered species. In this talk I'll survey the current state of the art in stream ciphers: who needs them, who uses them, how they are attacked, and how they can be protected by new types of constructions.

Authenticated Encryption (AE) is the cryptographic process of providing simultaneous confidentiality and integrity protection to messages. This approach is more efficient than applying a two-step process of providing confidentiality for a message by encrypting the message, and in a separate pass providing integrity protection by generating a Message Authentication Code (MAC). AE using symmetric...

Guess-and-determine attack is one of the general attacks on stream ciphers. It is a common cryptanalysis tool for evaluating security of stream ciphers. The effectiveness of this attack is based on the number of unknown bits which will be guessed by the attacker to break the cryptosystem. In this work, we present a relation between the minimum numbers of the guessed bits and uniquely restricted...

The encryption algorithms are designed to provide integrity and confidentiality of the messages. Modern cryptosystems are classified into three categories such as Block ciphers, Stream cipher and Hybrid ciphers of Hummingbird. This paper details about various types of block ciphers and stream ciphers. In this paper we also present the hybrid model of hummingbird and its comparison among other c...

In this paper we present a general framework for the application of the ideas of differential cryptanalysis to stream ciphers. We demonstrate that some differences in the key (or the initial state or the plaintext) are likely to cause predicted differences in the key stream or in the internal state. These stream differences can then be used to analyze the internal state of the cipher and retrie...

In modern cryptography, stream ciphers are most useful in applications where information needs to be encrypted/decrypted at high speed (e.g. high resolution streaming video data) or when low footprint (gates/memory) encryption is required. In the literature, there exist plenty of stream ciphers whose internal states are based on arrays and that they use modular additions to generate output stre...

Side-channel attacks on block ciphers and public key algorithms have been discussed extensively. However, there is only sparse literature about side-cannel attacks on stream ciphers. The few existing references mainly treat timing [8] and template attacks [10], or provide a theoretical analysis [6], [7] of weaknesses of stream cipher constructions. In this paper we present attacks on two focus ...