Talk:Stream cipher

message: I am changing the sentence "Stream ciphers typically execute at a higher speed in hardware but a much slower speed in software than block ciphers." because it isn't generally true. RC4, for example, is one of the fastest strong ciphers available in software. --agr 18:26, 17 Nov 2004 (UTC)
thread_title: Speeds

message: The patent indicated in the link actually points to a releasable pin.  I can't find the correct patent, but maybe some clever pedian can. —The preceding unsigned comment was added by 198.97.67.57 (talk) 16:58, 30 January 2007 (UTC)
thread_title: Errors

message: The sentence
:Another advantage of stream ciphers in military cryptography is that the cipher stream can be generated in a separate box that is subject to strict security measures and fed to other devices, e.g. a radio set, which will perform the xor operation as part of their function. The latter device can then be designed and used in less stringent environments.
looks questionable to me--any device that sees plaintext has to be designed stringently.  See Red-black separation.  I'd like to remove this sentence unless someone objects.  Phr 03:37, 9 April 2006 (UTC)
replies: text: I see what you're saying but I read this that the "crypto box" sees the pialntext, and then feeds the ciphertext to the radio DrVxD (talk) 19:21, 15 June 2008 (UTC)
thread_title: Military

message: I wonder if a comparison table is a good idea.  We found that trying to maintain one for ESTREAM was a pretty fraught business, especially when (as is the case with Py (cipher)) there's dispute about the validity of an attack.  And unlike with with ESTREAM, here the table may grow without bound.
I think it should list only ciphers that are widely used: RC4, A5/1, A5/2 etc.
On a minor note, the table suggests that there are linear cryptanalytic attacks on Salsa20.  I'm unaware of any published, unless you mean the papers by Li An-Ping which never made sense have been pretty thoroughly shredded.  — ciphergoth 05:51, 7 September 2006 (UTC)
replies: text: Is "eventually" gt 2.75 years, or did someone explain the color scheme to you via enciphered communication to your satisfaction?  — Preceding unsigned comment added by 71.83.65.241 (talk) 14:13, 1 November 2012 (UTC)
thread_title:  Comparison table 

message: I changed "In a stream cipher the plaintext digits are encrypted one at a time, and in which the transformation of successive digits varies during the encryption." to "In a stream cipher the plaintext digits are encrypted one at a time, and the transformation of successive digits varies during the encryption." because it didn't appear to make sense. If I was wrong, can someone who knows things please fix it?
Bitwiseb 20:43, 7 November 2007 (UTC)
thread_title:  Grammar in second sentence 

message: ..while stream ciphers eliminate this issue by naturally operating on the smallest unit that can be transmitted (usually bytes).
isn't a bit the smallest unit? stream ciphers can operate bitwise.  —Preceding unsigned comment added by 147.86.212.162 (talk) 08:28, 10 June 2008 (UTC)
replies: text: As stated in the article, stream ciphers just produce a pseudorandom keystream from the key and combine it with the plaintext (or ciphertext). Usually this is done using XOR which is already a bitwise operation. There is no plausible reason not to use XOR, so stream ciphers operate bitwise by the very nature of the encryption. 121.73.17.17 (talk) 02:35, 14 December 2010 (UTC)

text: There is a confusion between the notion of the smallest unit that can be processed. The first applies to the size of a symbol the keystream generator/stream cipher outputs. Usually, this is a byte for software-oriented stream ciphers because of the prevalence of byte-aligned memory addressing in current computer architectures, and a bit for hardware designs. Stream ciphers that implement pseudo-random functions have much larger symbol sizes (e.g., 64 bits). The second notion applies to the smallest unit of plaintext that can be processed. For additive stream ciphers, where the keystream is added with the plaintext in an exclusive-or style, this is naturally always a bit. HTH, Nageh (talk) 13:16, 14 December 2010 (UTC)
thread_title:  smallest unit