{"id":4506,"date":"2020-04-01T15:18:43","date_gmt":"2020-04-01T13:18:43","guid":{"rendered":"http:\/\/www.laurentmarot.fr\/wordpress\/?p=4506"},"modified":"2020-04-03T08:58:10","modified_gmt":"2020-04-03T06:58:10","slug":"rsa-cryptosystem-overview","status":"publish","type":"post","link":"https:\/\/www.laurentmarot.fr\/wordpress\/?p=4506","title":{"rendered":"RSA Cryptosystem overview"},"content":{"rendered":"<p>Juste besoin de cet execellent passage de <a href=\"https:\/\/en.wikipedia.org\/wiki\/RSA_(cryptosystem)\" target=\"_blank\" rel=\"noopener noreferrer\">Wikipedia<\/a> (20200401)<\/p>\n<p><b>RSA<\/b> (<b>Rivest\u2013Shamir\u2013Adleman<\/b>) is one of the first <a title=\"Public-key cryptography\" href=\"https:\/\/en.wikipedia.org\/wiki\/Public-key_cryptography\">public-key cryptosystems<\/a> and is widely used for secure data transmission. In such a <a title=\"Cryptosystem\" href=\"https:\/\/en.wikipedia.org\/wiki\/Cryptosystem\">cryptosystem<\/a>, the <a class=\"mw-redirect\" title=\"Encryption key\" href=\"https:\/\/en.wikipedia.org\/wiki\/Encryption_key\">encryption key<\/a> is public and distinct from the <a class=\"mw-redirect\" title=\"Decryption key\" href=\"https:\/\/en.wikipedia.org\/wiki\/Decryption_key\">decryption key<\/a> which is kept secret (private). In RSA, this asymmetry is based on the practical difficulty of <a title=\"Factorization\" href=\"https:\/\/en.wikipedia.org\/wiki\/Factorization\">factoring<\/a> the product of two large <a title=\"Prime number\" href=\"https:\/\/en.wikipedia.org\/wiki\/Prime_number\">prime numbers<\/a>, the \u00ab\u00a0<a class=\"mw-redirect\" title=\"Factoring problem\" href=\"https:\/\/en.wikipedia.org\/wiki\/Factoring_problem\">factoring problem<\/a>\u00ab\u00a0. The <a title=\"Acronym\" href=\"https:\/\/en.wikipedia.org\/wiki\/Acronym\">acronym<\/a> RSA is the initial letters of the surnames of <a title=\"Ron Rivest\" href=\"https:\/\/en.wikipedia.org\/wiki\/Ron_Rivest\">Ron Rivest<\/a>, <a title=\"Adi Shamir\" href=\"https:\/\/en.wikipedia.org\/wiki\/Adi_Shamir\">Adi Shamir<\/a>, and <a title=\"Leonard Adleman\" href=\"https:\/\/en.wikipedia.org\/wiki\/Leonard_Adleman\">Leonard Adleman<\/a>, who publicly described the algorithm in 1977. <a title=\"Clifford Cocks\" href=\"https:\/\/en.wikipedia.org\/wiki\/Clifford_Cocks\">Clifford Cocks<\/a>, an English mathematician working for the British intelligence agency <a class=\"mw-redirect\" title=\"Government Communications Headquarters\" href=\"https:\/\/en.wikipedia.org\/wiki\/Government_Communications_Headquarters\">Government Communications Headquarters<\/a> (GCHQ), had developed an equivalent system in 1973, which was not <a title=\"Classified information\" href=\"https:\/\/en.wikipedia.org\/wiki\/Classified_information\">declassified<\/a> until 1997.<sup id=\"cite_ref-1\" class=\"reference\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/RSA_(cryptosystem)#cite_note-1\">[1]<\/a><\/sup><\/p>\n<p>A user of RSA creates and then publishes a public key based on two large <a title=\"Prime number\" href=\"https:\/\/en.wikipedia.org\/wiki\/Prime_number\">prime numbers<\/a>, along with an auxiliary value. The prime numbers must be kept secret. Anyone can use the public key to encrypt a message, but only someone with knowledge of the prime numbers can decode the message.<sup id=\"cite_ref-rsa_2-0\" class=\"reference\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/RSA_(cryptosystem)#cite_note-rsa-2\">[2]<\/a><\/sup> Breaking RSA <a title=\"Encryption\" href=\"https:\/\/en.wikipedia.org\/wiki\/Encryption\">encryption<\/a> is known as the <a title=\"RSA problem\" href=\"https:\/\/en.wikipedia.org\/wiki\/RSA_problem\">RSA problem<\/a>. Whether it is as difficult as the <a class=\"mw-redirect\" title=\"Factoring problem\" href=\"https:\/\/en.wikipedia.org\/wiki\/Factoring_problem\">factoring problem<\/a> is an open question. There are no published methods to defeat the system if a large enough key is used.<\/p>\n<p>RSA is a relatively slow algorithm, and because of this, it is less commonly used to directly encrypt user data. More often, RSA passes encrypted shared keys for <a title=\"Symmetric-key algorithm\" href=\"https:\/\/en.wikipedia.org\/wiki\/Symmetric-key_algorithm\">symmetric key<\/a> cryptography which in turn can perform bulk encryption-decryption operations at much higher speed.<\/p>\n<p>&nbsp;<\/p>\n\n","protected":false},"excerpt":{"rendered":"<p>Juste besoin de cet execellent passage de Wikipedia (20200401) RSA (Rivest\u2013Shamir\u2013Adleman) is one of the first public-key cryptosystems and is widely used for secure data transmission. In such a cryptosystem, the encryption key is public and distinct from the decryption key which is kept secret (private). In RSA, this asymmetry is based on the practical [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4506"}],"collection":[{"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4506"}],"version-history":[{"count":2,"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4506\/revisions"}],"predecessor-version":[{"id":4508,"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4506\/revisions\/4508"}],"wp:attachment":[{"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4506"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4506"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laurentmarot.fr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4506"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}