# 1.  ## a  `openssl genrsa -out key.pem 1024`  ```  -----BEGIN PRIVATE KEY-----  MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAMZwcZmvikwKsPJZ  BdJ5PX+Jkp8UjEVcqkDquJgVFET9stJIxO2dhhLkrf2V4xybV+bAq9RGbzdosPXu  j/b3LQwQb786tyAIonS3QtElQyUcCm+bnLW+I9gK1eqd7mzzvd0OpTx5KeskLI0o  V1m0KLR2gU1kR/qQtzxm5kdJLp3fAgMBAAECgYEAsCqA32Q0jX9sSSn4/jo9+2xh  qzJtuOIkD0+RowoLnZfwWbjaguw2a61yPU8EeY/7QFLJ+MCy2WjquNoaGrCi3qNj  wsSO+3gkTZfKyf0VYQ+44XwcNHMvyvjZddPfUxz7OJOMeXZ/gnTIL7ZLiVbUXLVO  HEvhAxVsH7moGEbGBEECQQDrZrH2Js7DJrj1QBM79PB3/AKb5yey5tmUisI9vJaX  YWaBCa1fUP5lDpSY/GyQIJaP54QrytVZBmUcd/5Oy6BhAkEA183AYlcOEHfOKtPK  LMUgHla2pstLCJxAD03IFVXz/425RtY6t3mtRj16RGzpNttCnKmyyghhj/6liSrs  wNvmPwJAUbyi5nmrKY/0gRPymcr/BGp47XFiE3ic7DsSHyWwlHe5g+y8SnBxJN3f  Mw/TEmh+XxFgj2QqmHLkAPKZVvrVgQJAfdOVzMD9jlSMfSQnyZrWc1oT/YSjJ04T  e9jaRLZtIiA8WzUl3zyu7zmBRMxL3pRRbo7zlCD24cKUOjow+PI+eQJBAOWj8Z+3  Pcykk2vdxn2GOL2eNgE2ywe1BU8pjMboVT/i9nFRj+3CVFbHO37upiL65U9bl4vF  sdQc3etTvcu+kWo=  -----END PRIVATE KEY-----  ``` quelle: https://samsclass.info/141/proj/pCH-RKF.htm  ---  ## b  ### .pem (Privacy-Enhanced Mail):  Dateiformat für kryptographische Schlüssel.  ### ASN.1 (Abstract Syntax Notation One):  "eine Beschreibungssprache zur Definition von Datenstrukturen"  quellen:   - https://de.wikipedia.org/wiki/Privacy_Enhanced_Mail  - https://de.wikipedia.org/wiki/Abstract_Syntax_Notation_One  ---  ## c / d  `openssl rsa -in key.pem -text -inform PEM -noout`  ```  modulus:(n = pq)      00:a4:54:3b:f9:d9:0a:8e:01:be:51:0d:49:e3:d6:      17:c7:77:96:6b:75:02:8b:4b:f0:e1:8a:cc:14:39:      e0:d3:07:d1:2a:74:de:98:4d:6c:0a:e3:b4:88:c0:      b6:c7:47:38:3a:12:bf:e4:4e:67:a8:2f:85:10:bd:      b5:a8:a9:88:cc:96:cf:76:69:14:68:8f:e8:bb:ce:      35:5b:59:10:b5:7e:c2:a4:98:a5:43:87:c2:2e:60:      b4:81:5d:e1:49:60:d1:55:df:a5:ff:38:bb:5f:e9:      f0:b7:0c:d6:52:78:23:80:7a:55:1a:eb:92:3f:b0:      0b:14:18:48:c9:cb:a1:d2:7f  publicExponent: 65537 (0x10001) (e)  privateExponent: (d)      31:7d:d5:1a:68:8d:cf:3b:23:30:92:0a:00:fe:87:      e6:e1:53:82:45:99:60:8e:9c:9b:b1:0b:c9:c3:ac:      bc:a2:0c:12:f7:63:db:06:e6:55:59:43:14:34:c6:      57:ba:51:6a:dc:1e:c3:0a:02:1a:1b:45:be:47:04:      a1:29:7e:33:74:2b:4f:98:3e:83:ab:9f:6e:9f:27:      f1:91:80:4d:97:be:c8:00:f1:f4:72:4d:e4:9f:c9:      80:ef:59:72:5d:72:ca:d5:42:43:5d:70:50:7e:bd:      4f:87:6e:3d:ce:1c:5d:40:a3:a9:07:fb:75:29:04:      a8:61:e9:0d:6a:a7:ea:71  prime1: (p)      00:d9:cd:05:8b:ed:1d:49:9b:90:f4:a2:e8:2d:62:      2c:cd:ef:bb:68:74:72:c2:a3:fb:3b:27:32:5b:09:      51:b2:3d:72:29:61:03:da:5a:fb:71:8d:66:85:66:      c2:f9:84:77:8f:c3:79:03:29:cd:dc:60:20:2a:f8:      cf:d3:15:66:4b  prime2: (q)      00:c1:26:65:82:0d:2c:7b:76:b8:44:20:1f:ad:75:      d7:5d:94:02:96:3d:0a:82:36:fc:78:3f:17:3a:bd:      2c:e6:19:8d:bf:2d:b4:af:c0:fe:40:f5:03:d7:62:      a0:60:7a:1a:d3:e2:b9:7d:e4:8d:43:d5:79:d8:cd:      25:0f:8a:34:1d  exponent1: (dp)      57:be:12:b7:f6:44:50:3d:0d:be:a0:4a:6c:ce:1a:      42:b4:8b:89:5f:30:44:5d:8f:7e:9b:21:dc:2e:fa:      ec:95:78:82:57:05:18:58:82:e7:92:11:75:38:9a:      df:ae:90:04:28:b9:7d:9e:bf:c2:42:2f:73:60:5d:      49:2a:5b:d5  exponent2: (dq)      00:af:17:b1:99:4d:7b:ef:88:55:ce:5c:18:9b:54:      62:21:90:95:2f:c0:b2:10:0c:ec:9d:cd:03:af:d9:      e2:23:cd:32:74:06:68:ef:92:52:6a:6c:32:49:44:      3d:02:78:6e:6d:79:f0:91:31:68:e5:ff:55:6f:b5:      b8:4c:f8:09:f9  coefficient: (q inv)      00:8e:68:ff:dd:cd:ab:61:6d:91:88:5e:4b:ba:24:      d9:47:4f:24:3f:58:8f:21:a4:07:f2:c8:98:a5:5e:      be:45:06:d4:03:08:df:ec:a7:d0:db:48:5d:52:2b:      ff:86:e8:b3:5e:66:e5:79:c7:20:bc:4a:71:ca:ac:      c8:24:3a:3b:62  ``` quelle: https://crypto.stackexchange.com/questions/6593/what-data-is-saved-in-rsa-private-key  ---  ## e  Chinesischer Restsatz: Effizienteres verschlüsseln/signieren.  quelle: https://de.wikipedia.org/wiki/RSA-Kryptosystem#RSA_mit_dem_Chinesischen_Restsatz  ---  ## f  `openssl rsa -in key.pem -pubout > key.pub`  `openssl rsa -pubin -in key.pub -text`  ```  RSA Public-Key: (1024 bit)  Modulus:      00:a4:54:3b:f9:d9:0a:8e:01:be:51:0d:49:e3:d6:      17:c7:77:96:6b:75:02:8b:4b:f0:e1:8a:cc:14:39:      e0:d3:07:d1:2a:74:de:98:4d:6c:0a:e3:b4:88:c0:      b6:c7:47:38:3a:12:bf:e4:4e:67:a8:2f:85:10:bd:      b5:a8:a9:88:cc:96:cf:76:69:14:68:8f:e8:bb:ce:      35:5b:59:10:b5:7e:c2:a4:98:a5:43:87:c2:2e:60:      b4:81:5d:e1:49:60:d1:55:df:a5:ff:38:bb:5f:e9:      f0:b7:0c:d6:52:78:23:80:7a:55:1a:eb:92:3f:b0:      0b:14:18:48:c9:cb:a1:d2:7f  Exponent: 65537 (0x10001)  writing RSA key  -----BEGIN PUBLIC KEY-----  MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCkVDv52QqOAb5RDUnj1hfHd5Zr  dQKLS/DhiswUOeDTB9EqdN6YTWwK47SIwLbHRzg6Er/kTmeoL4UQvbWoqYjMls92  aRRoj+i7zjVbWRC1fsKkmKVDh8IuYLSBXeFJYNFV36X/OLtf6fC3DNZSeCOAelUa  65I/sAsUGEjJy6HSfwIDAQAB  -----END PUBLIC KEY-----  ``` quellen:  - https://stackoverflow.com/questions/5244129/use-rsa-private-key-to-generate-public-key  - https://superuser.com/questions/1644533/how-do-i-use-the-openssl-command-to-decode-a-public-key-pem-file  ---  ## g  `echo 'hey abc' | openssl rsautl -encrypt -pubin -inkey key.pub >message.encrypted`  ```  $ xxd message.encrypted  00000000: 9f6a 58aa ef1f bf17 8058 6e03 39f8 673b  .jX......Xn.9.g;  00000010: 6d3b ad1e b9b3 8f71 a7c2 0984 a0ff 5291  m;.....q......R.  00000020: a2ef 8a36 8132 3d61 7df7 105b e8c9 e07c  ...6.2=a}..[...|  00000030: fde7 5663 13f0 961b 63e8 2061 c3f7 253e  ..Vc....c. a..%>  00000040: e7bf 7711 8761 9a16 1ce9 b320 0903 4c58  ..w..a..... ..LX  00000050: 0b45 f506 4d5a 6c47 a4b9 4d32 6735 637b  .E..MZlG..M2g5c{  00000060: 648c c7d1 194c f263 6bfb 7bf8 a338 9dfc  d....L.ck.{..8..  00000070: 621e e772 3c4f c165 a6ce 0e1a 93a4 c031  b..r