Helix
A helix (pl: helixes or helices) is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helices are coil springs and the handrails of spiral staircases. A "filled-in" helix – for example, a spiral ramp – is called a helicoid. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word helix comes from the Greek word ἕλιξ, "twisted, curved".
Types
Helices can be either right-handed or left-handed. With the line of sight along the helix's axis, if a clockwise screwing motion moves the helix away from the observer, then it is called a right-handed helix; if towards the observer, then it is a left-handed helix. Handedness (or chirality) is a property of the helix, not of the perspective: a right-handed helix cannot be turned to look like a left-handed one unless it is viewed in a mirror, and vice versa.
Phelix
Phelix is a high-speed stream cipher with a built-in single-pass message authentication code (MAC) functionality, submitted in 2004 to the eSTREAM contest by Doug Whiting, Bruce Schneier, Stefan Lucks, and Frédéric Muller. The cipher uses only the operations of addition modulo 232, exclusive or, and rotation by a fixed number of bits. Phelix uses a 256-bit key and a 128-bit nonce, claiming a design strength of 128 bits. Concerns have been raised over the ability to recover the secret key if the cipher is used incorrectly.
Performance
Phelix is optimised for 32-bit platforms. The authors state that it can achieve up to eight cycles per byte on modern x86-based processors.
FPGA Hardware performance figures published in the paper "Review of stream cipher candidates from a low resource hardware perspective" are as follows:
Helix
Phelix is a slightly modified form of an earlier cipher, Helix, published in 2003 by Niels Ferguson, Doug Whiting, Bruce Schneier, John Kelsey, Stefan Lucks, and Tadayoshi Kohno; Phelix adds 128 bits to the internal state.
Ice
Ice is water frozen into a solid state. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color.
In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far as the Oort cloud. Beyond the Solar System, it occurs as interstellar ice. It is abundant on Earth's surface – particularly in the polar regions and above the snow line – and, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes.
Ice molecules can exhibit up to sixteen different phases (packing geometries) that depend on temperature and pressure. When water is cooled rapidly (quenching), up to three different types of amorphous ice can form depending on the history of its pressure and temperature. When cooled slowly correlated proton tunneling occurs below 20 K giving rise to macroscopic quantum phenomena. Virtually all the ice on Earth's surface and in its atmosphere is of a hexagonal crystalline structure denoted as ice Ih (spoken as "ice one h") with minute traces of cubic ice denoted as ice Ic. The most common phase transition to ice Ih occurs when liquid water is cooled below 0°C (273.15K, 32°F) at standard atmospheric pressure. It may also be deposited directly by water vapor, as happens in the formation of frost. The transition from ice to water is melting and from ice directly to water vapor is sublimation.
Ice (Nowra novel)
Ice is a 2008 novel by Australian novelist Louis Nowra.
Plot summary
A pair of ambitious young British entrepreneurs, Malcolm McEacharn and Andrew McIlwraith, charter a steamer with the aim of towing an iceberg from Antarctica to Sydney. The success of the venture transforms Sydney, and McEacharn who later becomes lord mayor of Melbourne.
Notes
Reviews
Awards and nominations
References
Ice (1998 film)
Ice is a 1998 television disaster film starring Grant Show, Udo Kier, and Eva La Rue. The film has a similar premise as The Day After Tomorrow, a science fiction disaster film released six years later. Though completely in English, it first premiered in Germany in 1998 before being aired on ABC in the United States in 2000.
Plot
A small meteor hits the sun, causing disastrous consequences for the Earth. Los Angeles is, just as the rest of the world, covered with a layer of ice and snow. The government has collapsed and everyone is on their own. Chaos and crime prevails. Together with scientist Dr. Kistler and a small group of survivors, L.A. cop Robert Drake leaves in the direction of Long Beach Harbor to meet with a government ship which will take them to Guam, where it is warmer.
Cast
Podcasts:
