Levels of attacks

There are four levels of attacks which one can make the assumption that a adversary can carry out. One calls attack an attempt at Cryptanalyse.

One of the fundamental axioms of the Cryptographie, stated for the first time by Auguste Kerckhoffs at the 19th century, is that the enemy all the details of the algorithm and that it has misses only the specific key for coding. For a detailed article, to see Principle of Kerckhoffs.

Goldwasser and Micali showed that the concept of safety compared to a attacks with selected text quantified is equivalent to that of semantic Sécurité.

Attacks

The attack with text only quantified ( ciphertext-only attack )

The cryptanalyste has the text quantified several messages, all having been quantified with the same algorithm. The task of the cryptanalyste is to find the greatest number of possible clear messages, or still to better find the keys which were used, which would make it possible to decipher other coded messages with these same keys.

See also:

  • Attack with text only quantified
  • IND-CCA

The attack with text clearly known ( known-plaintext attack )

The cryptanalyste has not only access to the quantified texts several messages, but also to the corresponding clear texts. The task is to find the keys which were used to quantify these messages or an algorithm which makes it possible to decipher other coded messages with these same keys.

See also:

  • Attack with text clearly known

The attack with text clearly selected ( chosen-plaintext attack )

The cryptanalyste has not only access to the quantified texts and the corresponding clear texts, but moreover it can choose the plaintexts. This attack is more effective than the attack with text clearly known, because the cryptanalyste can choose specific plaintexts which will give more information on the key.

See also:

  • hermetically-sealed IND-CPA1
  • Proceeded

The attack with selected quantified text ( adaptive-plaintext attack )

The cryptanalyste can choose various texts quantified to decipher. The deciphered texts are then provided to him. For example, the cryptanalyste has a device which cannot be disassembled and which makes automatic deciphering. Its task is to find the key.

See also:

  • IND-CPA2

References

  • S. Goldwasser and S. Micali, “Probabilistic encryption”, Newspaper off Computer and System Sciences , 28:270 - 299, 1984.

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