Details update

Thesis.bib

@@ -19,7 +19,7 @@ @online{monerokirk
   title = {Kirk Ransomware},
   year = 2017,
   url = {https://sensorstechforum.com/kirk-ransomware-remove-restore-kirked-files/},
-  urldate = {2019-31-03}
+  urldate = {2019-03-31}
 }
 @InProceedings{monerohistory,
 author="Sun, Shi-Feng
@@ -652,4 +652,33 @@ @article{konoth2019malicious
   journal   = {CoRR},	
   year      = {2019},
   eprint    = {1901.10794}
-}
+}
+
+@online{limesurvey,
+  author = {{LimeSurvey}},
+  title = {LimeSurvey - The most Popular FOSS Online Survey Tool on the Web},
+  year = 2019,
+  url = {https://github.com/LimeSurvey/LimeSurvey},
+  urldate = {2019-04-20}
+}
+
+@online{certbot,
+  author = {{Certbot}},
+  title = {The Certbot ACME Client},
+  year = 2019,
+  url = {https://github.com/certbot/certbot},
+  urldate = {2019-04-20}
+}
+
+
+@online{letsencrypt,
+  author = {{Let's Encrypt}},
+  title = {A Free, Automated, and Open Certificate Authority},
+  year = 2019,
+  url = {https://github.com/letsencrypt},
+  urldate = {2019-04-20}
+}
+
+
+
+