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Caesar cipher with a left shift of 3
Caesar cipher with a left shift of 3

A Caesar cipher, also known as Caesar's cipher, the shift cipher, Caesar's code, or the Caesar shift, is one of the simplest and most widely known encryption techniques in cryptography. Named after Julius Caesar, who is said to have used it, it is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a left shift of 3, D would be replaced by A, E would become B, and so on (pictured). Caesar is believed to have used one in his private correspondence, and a similar one was used by his nephew, Augustus. The encryption step performed by a Caesar cipher is often incorporated as part of more complex schemes, such as the Vigenère cipher, and still has modern application in the ROT13 system. As with all single-alphabet substitution ciphers, the Caesar cipher is easily broken and in modern practice offers essentially no communications security. (Full article...)

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Blackberry

The blackberry is an edible fruit produced by many species in the genus Rubus in the family Rosaceae. Blackberries are typically produced from hybrid plants among the species within the subgenus Rubus, or hybrids between the subgenera Rubus and Idaeobatus. Similar to the raspberry, it is not a berry in the botanical sense, being classified as an aggregate fruit composed of small drupelets. Blackberries are perennial plants bearing biennial stems from their roots. Unmanaged plants tend to aggregate in a dense tangle of stems and branches, which can be controlled in gardens or farms using trellises. Blackberry shrubs can tolerate poor soils, spreading readily in wasteland, ditches, and roadsides. Blackberries grow wild throughout most of Europe. They are an important element in the ecology of many countries, and harvesting the berries is a common pastime. In some parts of the world, however, there are blackberry species that are considered to be an invasive species. The fruit is also grown commercially, with Mexico being the leading producer, exporting for sale in off-season fresh markets in North America and Europe. This photograph, which was focus-stacked from 23 separate images, depicts a blackberry of the species Rubus fruticosus.

Photograph credit: Ivar Leidus

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