OpenSSL Introduction

To encrypt a text file use:

OpenSSL> enc -base64 -in myfile.txt

or
OpenSSL> enc -base64 -in myfile.txt -out myfile.txt.enc
or just a test using pipe
D:\git\bin>echo "Hello World" | openssl enc -base64
To decrypt, use
OpenSSL> enc -base64 -d -in myfile.txt.enc
To decrypt from pipe, use
D:\git\bin>echo "encrypted" | openssl enc -base64 -d
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OpenSSL Introduction