{"id":213,"date":"2011-01-11T08:53:26","date_gmt":"2011-01-11T07:53:26","guid":{"rendered":"https:\/\/thebc.ch\/blog\/?p=213"},"modified":"2013-02-01T13:18:26","modified_gmt":"2013-02-01T12:18:26","slug":"about-hashes-keys-and-ciphers","status":"publish","type":"post","link":"https:\/\/thebc.ch\/blog\/?p=213","title":{"rendered":"About Hashes Keys and Ciphers"},"content":{"rendered":"<div id=\"toctitle\">\n<span id=\"Contents\"><h2>Contents<\/h2><\/span>\n<\/div>\n<ul>\n<li>1 Hashes\n<ul>\n<li>1.1 General<\/li>\n<li>1.2 Different encryptions and lenght<\/li>\n<\/ul>\n<\/li>\n<li>2 Algorithm\n<ul>\n<li>2.1 MD5 \u00e2\u20ac\u201c Message Digest #5<\/li>\n<li>2.2 SHA-1 \u00e2\u20ac\u201c Secure Hash Algorithm<\/li>\n<li>2.3 RIPEMD-160<\/li>\n<\/ul>\n<\/li>\n<li>3 Collisions<\/li>\n<li>4 Encryption Methods\n<ul>\n<li>4.1 Symmetric key cryptography\n<ul>\n<li>4.1.1 Stream ciphers<\/li>\n<li>4.1.2 Block ciphers<\/li>\n<li>4.1.3 Cipher Block Modes<\/li>\n<\/ul>\n<\/li>\n<li>4.2 Asymmetric key \/ Public key cryptography\n<ul>\n<li>4.2.1 Nachteile<\/li>\n<li>4.2.2 Algorithmen<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>5 \u00c3\u201equivalente kryptographische St\u00c3\u00a4rken<\/li>\n<li>6 Angriffe welche mit Kryptografie &#8220;bek\u00c3\u00a4mpft&#8221; werden k\u00c3\u00b6nnen<\/li>\n<\/ul>\n<p><a id=\"Hashes\" name=\"Hashes\"><\/a><\/p>\n<span id=\"Hashes\"><h2>Hashes<\/h2><\/span>\n<p><a id=\"General\" name=\"General\"><\/a><\/p>\n<span id=\"General\"><h3>General<\/h3><\/span>\n<p>128-bit hash can have 2<sup>128<\/sup> possible values, which is:<\/p>\n<pre>340,282,366,920,938,463,463,374,607,431,768,211,456<\/pre>\n<p>possible hashes<\/p>\n<p>512-bit can have 2<sup>512<\/sup> possible values, which is:<\/p>\n<pre> 13,407,807,929,942,597,099,574,024,998,205,846,127,479,\r\n365,820,592,393,377,723,561,443,721,764,030,073,546,976,\r\n801,874,298,166,903,427,690,031,858,186,486,050,853,753,\r\n882,811,946,569,946,433,649,006,084,096<\/pre>\n<p>possible hashes\u00c2\u00a0\ud83d\ude42<\/p>\n<p><a id=\"Different_encryptions_and_lenght\" name=\"Different_encryptions_and_lenght\"><\/a><\/p>\n<span id=\"Different_encryptions_and_lenght\"><h3>Different encryptions and lenght<\/h3><\/span>\n<pre>Parity-Bit    1 Bit\r\nCRC-16       16 Bit\r\nCRC-32       32 Bit\r\nHMAC         96 Bit\r\nMD4         128 Bit   (obsolete) <a title=\"http:\/\/en.wikipedia.org\/wiki\/MD4\" href=\"http:\/\/en.wikipedia.org\/wiki\/MD4\" rel=\"nofollow\">http:\/\/en.wikipedia.org\/wiki\/MD4<\/a>\r\nMD5         128 Bit   <a title=\"http:\/\/en.wikipedia.org\/wiki\/MD5\" href=\"http:\/\/en.wikipedia.org\/wiki\/MD5\" rel=\"nofollow\">http:\/\/en.wikipedia.org\/wiki\/MD5<\/a>\r\nRIPEMD-128  128 Bit\r\nRIPEMD160   160 Bit   <a title=\"http:\/\/en.wikipedia.org\/wiki\/RIPEMD-160\" href=\"http:\/\/en.wikipedia.org\/wiki\/RIPEMD-160\" rel=\"nofollow\">http:\/\/en.wikipedia.org\/wiki\/RIPEMD-160<\/a>\r\nSHA1        160 Bit   <a title=\"http:\/\/en.wikipedia.org\/wiki\/SHA\" href=\"http:\/\/en.wikipedia.org\/wiki\/SHA\" rel=\"nofollow\">http:\/\/en.wikipedia.org\/wiki\/SHA<\/a>\r\nSHA256      256 Bit\r\nSHA384      384 Bit\r\nSHA512      512 Bit<\/pre>\n<p>&nbsp;<\/p>\n<p><a id=\"Algorithm\" name=\"Algorithm\"><\/a><\/p>\n<span id=\"Algorithm\"><h2>Algorithm<\/h2><\/span>\n<p><a id=\"MD5_.E2.80.93_Message_Digest_.235\" name=\"MD5_.E2.80.93_Message_Digest_.235\"><\/a><\/p>\n<span id=\"MD5__Message_Digest_5\"><h3>MD5 \u00e2\u20ac\u201c Message Digest #5<\/h3><\/span>\n<ul>\n<li>Invented by Ron Rivest (the R in RSA) of RSA Security Inc.<\/li>\n<li>MD5 computes a hash value of 128 bits (16 bytes) out of an arbitrary-sized binary document.<\/li>\n<\/ul>\n<p><a id=\"SHA-1_.E2.80.93_Secure_Hash_Algorithm\" name=\"SHA-1_.E2.80.93_Secure_Hash_Algorithm\"><\/a><\/p>\n<span id=\"SHA-1__Secure_Hash_Algorithm\"><h3>SHA-1 \u00e2\u20ac\u201c Secure Hash Algorithm<\/h3><\/span>\n<ul>\n<li>Developed by the US National Institute of Standards and Technology (NIST) with the assistance of the National Security Agency (NSA).<\/li>\n<li>SHA-0 or simply SHA was published in 1993 as FIPS-180 by NIST. Due to a non-disclosed flaw it was withdrawn by NSA shortly after publication. The revised version, commonly referred to as SHA-1 was published in 1995 in the standard FIPS 180-1.<\/li>\n<li>SHA-1 computes a hash value of 160 bits (20 bytes) out of an arbitrary-sized binary document. The algorithm is similar to MD5 but is computationally more expensive.<\/li>\n<li>SHA-1 is more secure than MD5 due to its increased hash size.<\/li>\n<li>An improved family of algorithms with hash sizes of 256 bits (32 bytes), 384 bits (48 bytes) and 512 bits (64 bytes) was published by NIST in the standard FIPS-180-2 in August 2002 in order to keep up with the increased key sizes of the Advanced Encryption Standard (AES). These new hash algorithms are named according to their key sizes SHA-256, SHA-384, and SHA-512, respectively.<\/li>\n<\/ul>\n<p><a id=\"RIPEMD-160\" name=\"RIPEMD-160\"><\/a><\/p>\n<span id=\"RIPEMD-160\"><h3>RIPEMD-160<\/h3><\/span>\n<ul>\n<li>160 bit hash function developed by Hans Dobbertin, Antoon Bosselaers and Bart Preneel as part of a<\/li>\n<\/ul>\n<p>research project commissioned by the EU. It&#8217;s similar in both strength and performance to the much more popular SHA-1 hash function.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><a id=\"Collisions\" name=\"Collisions\"><\/a><\/p>\n<span id=\"Collisions\"><h2>Collisions<\/h2><\/span>\n<p>A collision is when two different files produces the same hash-sum.<\/p>\n<div class=\"codecolorer-container text default\" style=\"overflow:auto;white-space:nowrap;width:100%;\"><table cellspacing=\"0\" cellpadding=\"0\"><tbody><tr><td class=\"line-numbers\"><div>1<br \/><\/div><\/td><td><div class=\"text codecolorer\">#!\/usr\/bin\/perl -w<\/div><\/td><\/tr><\/tbody><\/table><\/div>\n<p>use strict;<\/p>\n<p>my $v1=&lt;&lt;END_V1; d1 31 dd 02 c5 e6 ee c4 69 3d 9a 06 98 af f9 5c 2f ca b5 87 12 46 7e ab 40 04 58 3e b8 fb 7f 89 55 ad 34 06 09 f4 b3 02 83 e4 88 83 25 71 41 5a 08 51 25 e8 f7 cd c9 9f d9 1d bd f2 80 37 3c 5b d8 82 3e 31 56 34 8f 5b ae 6d ac d4 36 c9 19 c6 dd 53 e2 b4 87 da 03 fd 02 39 63 06 d2 48 cd a0 e9 9f 33 42 0f 57 7e e8 ce 54 b6 70 80 a8 0d 1e c6 98 21 bc b6 a8 83 93 96 f9 65 2b 6f f7 2a 70 END_V1<\/p>\n<p>my $v2=&lt;&lt;END_V2; d1 31 dd 02 c5 e6 ee c4 69 3d 9a 06 98 af f9 5c 2f ca b5 07 12 46 7e ab 40 04 58 3e b8 fb 7f 89 55 ad 34 06 09 f4 b3 02 83 e4 88 83 25 f1 41 5a 08 51 25 e8 f7 cd c9 9f d9 1d bd 72 80 37 3c 5b d8 82 3e 31 56 34 8f 5b ae 6d ac d4 36 c9 19 c6 dd 53 e2 34 87 da 03 fd 02 39 63 06 d2 48 cd a0 e9 9f 33 42 0f 57 7e e8 ce 54 b6 70 80 28 0d 1e c6 98 21 bc b6 a8 83 93 96 f9 65 ab 6f f7 2a 70 END_V2<\/p>\n<p>my $p=join(&#8220;&#8221;,map {chr(hex($_))} split \/\\s+\/, $v1); my $q=join(&#8220;&#8221;,map {chr(hex($_))} split \/\\s+\/, $v2);<\/p>\n<p>print `echo -n \\&#8217;$p\\&#8217;|md5sum`; print `echo -n \\&#8217;$q\\&#8217;|md5sum`;<\/p>\n<p><a id=\"Encryption_Methods\" name=\"Encryption_Methods\"><\/a><\/p>\n<span id=\"Encryption_Methods\"><h2>Encryption Methods<\/h2><\/span>\n<p><a id=\"Symmetric_key_cryptography\" name=\"Symmetric_key_cryptography\"><\/a><\/p>\n<span id=\"Symmetric_key_cryptography\"><h3>Symmetric key cryptography<\/h3><\/span>\n<p><a id=\"Stream_ciphers\" name=\"Stream_ciphers\"><\/a><\/p>\n<span id=\"Stream_ciphers\"><h4>Stream ciphers<\/h4><\/span>\n<p><strong>Algorithms:<\/strong><br \/>\n<a title=\"http:\/\/en.wikipedia.org\/wiki\/A5\/1\" href=\"http:\/\/en.wikipedia.org\/wiki\/A5\/1\" rel=\"nofollow\">A5\/1<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/A5\/2\" href=\"http:\/\/en.wikipedia.org\/wiki\/A5\/2\" rel=\"nofollow\">A5\/2<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/FISH_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/FISH_%28cipher%29\" rel=\"nofollow\">FISH<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Grain_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/Grain_%28cipher%29\" rel=\"nofollow\">Grain<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/ISAAC_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/ISAAC_%28cipher%29\" rel=\"nofollow\">ISAAC<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/MUGI\" href=\"http:\/\/en.wikipedia.org\/wiki\/MUGI\" rel=\"nofollow\">MUGI<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Panama_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/Panama_%28cipher%29\" rel=\"nofollow\">Panama<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Phelix\" href=\"http:\/\/en.wikipedia.org\/wiki\/Phelix\" rel=\"nofollow\">Phelix<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Pike_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/Pike_%28cipher%29\" rel=\"nofollow\">Pike<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/RC4\" href=\"http:\/\/en.wikipedia.org\/wiki\/RC4\" rel=\"nofollow\">RC4<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Salsa20\" href=\"http:\/\/en.wikipedia.org\/wiki\/Salsa20\" rel=\"nofollow\">Salsa20<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Scream_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/Scream_%28cipher%29\" rel=\"nofollow\">Scream<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/SEAL_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/SEAL_%28cipher%29\" rel=\"nofollow\">SEAL<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/SOBER\" href=\"http:\/\/en.wikipedia.org\/wiki\/SOBER\" rel=\"nofollow\">SOBER<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/SOBER-128\" href=\"http:\/\/en.wikipedia.org\/wiki\/SOBER-128\" rel=\"nofollow\">SOBER-128<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Trivium_(cipher)\" href=\"http:\/\/en.wikipedia.org\/wiki\/Trivium_%28cipher%29\" rel=\"nofollow\">Trivium<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/VEST\" href=\"http:\/\/en.wikipedia.org\/wiki\/VEST\" rel=\"nofollow\">VEST<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/WAKE\" href=\"http:\/\/en.wikipedia.org\/wiki\/WAKE\" rel=\"nofollow\">WAKE<\/a><\/p>\n<p><a id=\"Block_ciphers\" name=\"Block_ciphers\"><\/a><\/p>\n<span id=\"Block_ciphers\"><h4>Block ciphers<\/h4><\/span>\n<p>A block cipher is a type of symmetric-key encryption algorithm that transforms a fixed-length block of plaintext (unencrypted text) data into a block of ciphertext (encrypted text) data of the same length. This transformation takes place under the action of a user-provided secret key. Decryption is performed by applying the reverse transformation to the ciphertext block using the same secret key. The fixed length is called the block size, and for many block ciphers, the block size is 64 bits. In the coming years the block size will increase to 128 bits as processors become more sophisticated.<\/p>\n<p><strong>Algorithms:<\/strong><br \/>\n<a title=\"http:\/\/en.wikipedia.org\/wiki\/3-Way\" href=\"http:\/\/en.wikipedia.org\/wiki\/3-Way\" rel=\"nofollow\">3-Way<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Advanced_Encryption_Standard\" href=\"http:\/\/en.wikipedia.org\/wiki\/Advanced_Encryption_Standard\" rel=\"nofollow\">AES<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Akelarre_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Akelarre_%28cipher%29\" rel=\"nofollow\">Akelarre<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Anubis_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Anubis_%28cipher%29\" rel=\"nofollow\">Anubis<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Blowfish_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Blowfish_%28cipher%29\" rel=\"nofollow\">Blowfish<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Camellia_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Camellia_%28cipher%29\" rel=\"nofollow\">Camellia<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/CAST-128\" href=\"http:\/\/en.wikipedia.org\/wiki\/CAST-128\" rel=\"nofollow\">CAST-128<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/CAST-256\" href=\"http:\/\/en.wikipedia.org\/wiki\/CAST-256\" rel=\"nofollow\">CAST-256<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/CMEA_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/CMEA_%28cipher%29\" rel=\"nofollow\">CMEA<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/CS-Cipher\" href=\"http:\/\/en.wikipedia.org\/wiki\/CS-Cipher\" rel=\"nofollow\">CS-Cipher<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/DEAL\" href=\"http:\/\/en.wikipedia.org\/wiki\/DEAL\" rel=\"nofollow\">DEAL<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Data_Encryption_Standard\" href=\"http:\/\/en.wikipedia.org\/wiki\/Data_Encryption_Standard\" rel=\"nofollow\">DES<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/DES-X\" href=\"http:\/\/en.wikipedia.org\/wiki\/DES-X\" rel=\"nofollow\">DES-X<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/FEAL\" href=\"http:\/\/en.wikipedia.org\/wiki\/FEAL\" rel=\"nofollow\">FEAL<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/FOX_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/FOX_%28cipher%29\" rel=\"nofollow\">FOX<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/FROG\" href=\"http:\/\/en.wikipedia.org\/wiki\/FROG\" rel=\"nofollow\">FROG<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/G-DES\" href=\"http:\/\/en.wikipedia.org\/wiki\/G-DES\" rel=\"nofollow\">G-DES<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/GOST_28147-89\" href=\"http:\/\/en.wikipedia.org\/wiki\/GOST_28147-89\" rel=\"nofollow\">GOST<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/ICE_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/ICE_%28cipher%29\" rel=\"nofollow\">ICE<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/International_Data_Encryption_Algorithm\" href=\"http:\/\/en.wikipedia.org\/wiki\/International_Data_Encryption_Algorithm\" rel=\"nofollow\">IDEA<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Iraqi_block_cipher\" href=\"http:\/\/en.wikipedia.org\/wiki\/Iraqi_block_cipher\" rel=\"nofollow\">Iraqi<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/KASUMI\" href=\"http:\/\/en.wikipedia.org\/wiki\/KASUMI\" rel=\"nofollow\">KASUMI<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/KHAZAD\" href=\"http:\/\/en.wikipedia.org\/wiki\/KHAZAD\" rel=\"nofollow\">KHAZAD<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Khufu_and_Khafre\" href=\"http:\/\/en.wikipedia.org\/wiki\/Khufu_and_Khafre\" rel=\"nofollow\">Khufu and Khafre<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/LOKI\" href=\"http:\/\/en.wikipedia.org\/wiki\/LOKI\" rel=\"nofollow\">LOKI89\/91<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/LOKI97\" href=\"http:\/\/en.wikipedia.org\/wiki\/LOKI97\" rel=\"nofollow\">LOKI97<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Lucifer_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Lucifer_%28cipher%29\" rel=\"nofollow\">Lucifer<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/MacGuffin_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/MacGuffin_%28cipher%29\" rel=\"nofollow\">MacGuffin<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Madryga\" href=\"http:\/\/en.wikipedia.org\/wiki\/Madryga\" rel=\"nofollow\">Madryga<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/MAGENTA_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/MAGENTA_%28cipher%29\" rel=\"nofollow\">MAGENTA<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/MARS\" href=\"http:\/\/en.wikipedia.org\/wiki\/MARS\" rel=\"nofollow\">MARS<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/MISTY1\" href=\"http:\/\/en.wikipedia.org\/wiki\/MISTY1\" rel=\"nofollow\">MISTY1<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/MMB\" href=\"http:\/\/en.wikipedia.org\/wiki\/MMB\" rel=\"nofollow\">MMB<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/NewDES\" href=\"http:\/\/en.wikipedia.org\/wiki\/NewDES\" rel=\"nofollow\">NewDES<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Noekeon\" href=\"http:\/\/en.wikipedia.org\/wiki\/Noekeon\" rel=\"nofollow\">Noekeon<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/RC2\" href=\"http:\/\/en.wikipedia.org\/wiki\/RC2\" rel=\"nofollow\">RC2<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/RC5\" href=\"http:\/\/en.wikipedia.org\/wiki\/RC5\" rel=\"nofollow\">RC5<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/RC6\" href=\"http:\/\/en.wikipedia.org\/wiki\/RC6\" rel=\"nofollow\">RC6<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/REDOC\" href=\"http:\/\/en.wikipedia.org\/wiki\/REDOC\" rel=\"nofollow\">REDOC<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Red_Pike\" href=\"http:\/\/en.wikipedia.org\/wiki\/Red_Pike\" rel=\"nofollow\">Red Pike<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/S-1\" href=\"http:\/\/en.wikipedia.org\/wiki\/S-1\" rel=\"nofollow\">S-1<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/SAFER\" href=\"http:\/\/en.wikipedia.org\/wiki\/SAFER\" rel=\"nofollow\">SAFER<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/SEED\" href=\"http:\/\/en.wikipedia.org\/wiki\/SEED\" rel=\"nofollow\">SEED<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Serpent_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Serpent_%28cipher%29\" rel=\"nofollow\">Serpent<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/SHACAL\" href=\"http:\/\/en.wikipedia.org\/wiki\/SHACAL\" rel=\"nofollow\">SHACAL<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/SHARK\" href=\"http:\/\/en.wikipedia.org\/wiki\/SHARK\" rel=\"nofollow\">SHARK<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Skipjack_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Skipjack_%28cipher%29\" rel=\"nofollow\">Skipjack<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Square_%28cipher%29\" href=\"http:\/\/en.wikipedia.org\/wiki\/Square_%28cipher%29\" rel=\"nofollow\">Square<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Tiny_Encryption_Algorithm\" href=\"http:\/\/en.wikipedia.org\/wiki\/Tiny_Encryption_Algorithm\" rel=\"nofollow\">TEA<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Triple_DES\" href=\"http:\/\/en.wikipedia.org\/wiki\/Triple_DES\" rel=\"nofollow\">Triple DES<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/Twofish\" href=\"http:\/\/en.wikipedia.org\/wiki\/Twofish\" rel=\"nofollow\">Twofish<\/a> | <a title=\"http:\/\/en.wikipedia.org\/wiki\/XTEA\" href=\"http:\/\/en.wikipedia.org\/wiki\/XTEA\" rel=\"nofollow\">XTEA<\/a><\/p>\n<p><a id=\"Cipher_Block_Modes\" name=\"Cipher_Block_Modes\"><\/a><\/p>\n<span id=\"Cipher_Block_Modes\"><h4>Cipher Block Modes<\/h4><\/span>\n<ul>\n<li>ECB &#8211; Electronic codebook<\/li>\n<li>CBC &#8211; Cipher-block chaining<\/li>\n<\/ul>\n<dl>\n<dd>CBC verhindert, dass gleiche Dateien nach der Verschl\u00c3\u00bcsselung gleich aussehen &#8211; das alte Verfahren ECB sorgt daf\u00c3\u00bcr, dass jede verschl\u00c3\u00bcsselte Datei immer wieder gleich aussieht (Stichwort Bijektivit\u00c3\u00a4t). So kann man leicht erkennen, ob eine bestimmte Datei mehrfach auf der Festplatte liegt. Au\u00c3\u0178erdem kann dies genutzt werden, um z.B. ganze Bl\u00c3\u00b6cke zu identifizieren und zu \u00c3\u00bcbersetzen, wenn man einige Teile der Festplatte schon kennt, was bei Standardsystemen der Fall ist (z.B. Informationen \u00c3\u00bcber das Dateisystem, etc.)<\/dd>\n<\/dl>\n<dl>\n<dd>Um dies zu verhindern, nutzt man CBC, das bei der Verschl\u00c3\u00bcsselung auch Informationen von dem vorher verschl\u00c3\u00bcsseltem Sektor mit einflie\u00c3\u0178en l\u00c3\u00a4sst. So sieht jeder verschl\u00c3\u00bcsselte Bereich anders aus, und kann nicht reproduziert werden.<\/dd>\n<\/dl>\n<ul>\n<li>CFB &#8211; Cipher feedback<\/li>\n<li>OFB &#8211; Output feedback<\/li>\n<li>CTR &#8211; Counter<\/li>\n<li>ESSIV (encrypted sector | salt initial vector)<\/li>\n<\/ul>\n<dl>\n<dd>ESSIV sorgt daf\u00c3\u00bcr, dass Watermarking-Angriffe erfolglos bleiben. Bei diesen Angriffen versucht man, mit Hilfe einer speziell pr\u00c3\u00a4parierten Datei, die man z.B. per Spam-Mail auf einen Rechner senden kann, herauszufinden, ob diese Datei auf der Festplatte liegt, und wenn ja, wo in etwa. Das Wasserzeichen schimmert quasi durch die Verschl\u00c3\u00bcsslung durch, wenn man gezielt danach sucht.<\/dd>\n<\/dl>\n<dl>\n<dd>Dies erfordert aber, dass der Initialisierungsvektor recht einfach berechnet werden kann, was ESSIV verhindert. Bei dem alten Verfahren plain k\u00c3\u00b6nnen hingegen Watermarking-Angriffe zum Erfolg f\u00c3\u00bchren.<\/dd>\n<\/dl>\n<dl>\n<dd>ESSIV kann derzeit als Option nur sha256 oder md5 entgegen nehmen &#8211; alle anderen implementierungen sind noch nicht in Standardpaketen verf\u00c3\u00bcgbar (Stand Juli 2005).<\/dd>\n<\/dl>\n<p><a id=\"Asymmetric_key_.2F_Public_key_cryptography\" name=\"Asymmetric_key_.2F_Public_key_cryptography\"><\/a><\/p>\n<span id=\"Asymmetric_key__Public_key_cryptography\"><h3>Asymmetric key \/ Public key cryptography<\/h3><\/span>\n<p>Der Schl\u00c3\u00bcssel ist in 2 Teile aufgeteilt, einen \u00c3\u00b6ffentlichen und einen geheimen. Der geheime Teil des Schl\u00c3\u00bcsselpaares ist nur einer Stelle bekannt. Der Nachteil der symmetrischen Verfahren existiert hier nicht, es braucht nur n , resp. 2n Schl\u00c3\u00bcsselpaare.<\/p>\n<p><a id=\"Nachteile\" name=\"Nachteile\"><\/a><\/p>\n<span id=\"Nachteile\"><h4>Nachteile<\/h4><\/span>\n<p>Der gr\u00c3\u00b6sste Nachteil ist der erh\u00c3\u00b6hte Rechenaufwand.<\/p>\n<p><a id=\"Algorithmen\" name=\"Algorithmen\"><\/a><\/p>\n<span id=\"Algorithmen\"><h4>Algorithmen<\/h4><\/span>\n<ul>\n<li>RSA<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p><a id=\".C3.84quivalente_kryptographische_St.C3.A4rken\" name=\".C3.84quivalente_kryptographische_St.C3.A4rken\"><\/a><\/p>\n<span id=\"quivalente_kryptographische_Strken\"><h2>\u00c3\u201equivalente kryptographische St\u00c3\u00a4rken<\/h2><\/span>\n<pre>  Sym.        RSA n    ECC p         Rate der Schl\u00c3\u00bcsselgr\u00c3\u00b6ssen\r\n  (in Bit)    (in Bit) (in Bit)  Sym\u00c2\u00a0: RSA    Sym\u00c2\u00a0: ECC   RSA\u00c2\u00a0: ECC\r\n     56         512      112     1:9          1:2         5:1\r\n     80        1024      160     1\u00c2\u00a0: 13       1:2         6:1\r\n    112        2048      224     1\u00c2\u00a0: 18       1:2         9:1\r\n    128        3072      256     1\u00c2\u00a0: 24       1:2         12\u00c2\u00a0: 1\r\n    192        7680      384     1\u00c2\u00a0: 40       1:2         20\u00c2\u00a0: 1\r\n    256       15\u00e2\u20ac\u2122360     512     1\u00c2\u00a0: 60       1:2         30\u00c2\u00a0: 1<\/pre>\n<p>&nbsp;<\/p>\n<p><a id=\"Angriffe_welche_mit_Kryptografie_.22bek.C3.A4mpft.22_werden_k.C3.B6nnen\" name=\"Angriffe_welche_mit_Kryptografie_.22bek.C3.A4mpft.22_werden_k.C3.B6nnen\"><\/a><\/p>\n<span id=\"Angriffe_welche_mit_Kryptografie_8220bekmpft8221_werden_knnen\"><h2>Angriffe welche mit Kryptografie &#8220;bek\u00c3\u00a4mpft&#8221; werden k\u00c3\u00b6nnen<\/h2><\/span>\n<ul>\n<li>Abh\u00c3\u00b6ren einer Meldung (Confidentiality) &#8211;&gt; symmetrische\/ asymmetrische Verschl\u00c3\u00bcsselung<\/li>\n<li>Ver\u00c3\u00a4ndern der Meldung (Integrity) &#8211;&gt; MAC Berechnung (sym.) \/ Digitale SIgnatur (asym)<\/li>\n<li>Eine erfundene Meldung einspielen (Insertion) &#8211;&gt; MAC Berechnung (sym.) \/ Digitale Signatur (asym)<\/li>\n<li>Abstreiten die Meldung geschickt zu haben (Non repudiation of origin) &#8211;&gt; Digitale Signatur (asym)<\/li>\n<li>Eine Meldung abfangen und sp\u00c3\u00a4ter wieder einspielen (Replay) &#8211;&gt; MAC und Sequenznummer (sym) \/ Digitale Signatur und Sequenznummer (asym)<\/li>\n<li>L\u00c3\u00b6schen von Meldungen (Delete). &#8211;&gt; MAC und Sequenznummer (sym) \/ Digitale Signatur und Sequenznummer (asym)<\/li>\n<li>Sich f\u00c3\u00bcr jemanden anders ausgeben (Masquerade)<\/li>\n<li>Abstreiten die Meldung erhalten zu haben (Non repudiation of receipt).<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Contents 1 Hashes 1.1 General 1.2 Different encryptions and lenght 2 Algorithm 2.1 MD5 \u00e2\u20ac\u201c Message Digest #5 2.2 SHA-1 \u00e2\u20ac\u201c Secure Hash Algorithm 2.3 RIPEMD-160 3 Collisions 4 Encryption Methods 4.1 Symmetric key cryptography 4.1.1 Stream ciphers 4.1.2 Block &hellip; <a href=\"https:\/\/thebc.ch\/blog\/?p=213\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[],"class_list":["post-213","post","type-post","status-publish","format-standard","hentry","category-security"],"_links":{"self":[{"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=\/wp\/v2\/posts\/213","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=213"}],"version-history":[{"count":6,"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=\/wp\/v2\/posts\/213\/revisions"}],"predecessor-version":[{"id":2733,"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=\/wp\/v2\/posts\/213\/revisions\/2733"}],"wp:attachment":[{"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=213"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=213"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thebc.ch\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=213"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}