In my last video, I discussed HTTP Basic authentication. I also demonstrated that some network protocol analyzers like Wireshark can decode the Base64 encoding scheme used by HTTP Basic.
In this video, I show you – using Wireshark -- that even the Simple Mail Transfer Protocol (SMTP) can use Base64 encoding as a very basic, weak form of encryption.
Base64 is a binary-to-text encoding scheme that is generally used to transfer content-based messages and works by dividing every three bits of binary data into six bit units. This new data is represented in a 64-radix numeral system and as seven-bit ASCII text. Because each bit is divided into two bits, the converted data is 33%, or one-third, larger than the original data. Like binary data, Base64-encoded resultant data is not human readable.
The lesson here would be to be aware of what form of encryption you are using.