daniftodi

# generate keys
openssl req -new -x509 -newkey rsa:4096 -keyout private.pem -sigopt rsa_padding_mode:pss -sha256 -sigopt rsa_pss_saltlen:64 -out public.pem -nodes

# openssl can't read PEM format, convert the key
openssl rsa -in private.pem -pubout > public.rsa

# sign a file, save the signature
openssl dgst -sign private.pem file.txt > signature.txt

# verify the file using signature

daniftodi

Note for me to remember how to set Android Home on Mac 

Open Terminal and type in..
nano ~/.bash_profile
Add the below paths
The path should be where your android installation is located
export ANDROID_HOME=/Users/username/Library/Android/sdk
export PATH=${PATH}:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools
Save file and type in terminal...
source ~/.bash_profile

daniftodi

Symmetic encryption

For symmetic encryption, you can use the following:

To encrypt:

openssl aes-256-cbc -salt -a -e -in plaintext.txt -out encrypted.txt

To decrypt:

daniftodi

Free O'Reilly books and convenient script to just download them.

Thanks /u/FallenAege/ and /u/ShPavel/ from this Reddit post

How to use:

1. Take the download.sh file and put it into a directory where you want the files to be saved.
2. cd into the directory and make sure that it has executable permissions (chmod +x download.sh should do it)
3. Run ./download.sh and wee there it goes. Also if you do not want all the files, just simply comment the ones you do not want.