It is likely that your analytical platform of choice has the option for decoding Base64, among other various encoding schemes. In the event that Base64 decoding is not an option, there are many web-based applications available to assist with decoding and encoding data. Common ASCII is not the only content that is often decoded. Data, such as image files, can be encoded and compressed. To see if your data is Base64 encoded, load it into a web-based converter and view the original file contents.^{1, 2}

Third-party application content should be thoroughly reviewed for the use of data encoding. Pay particular attention to messaging applications, as Base64 was first used for the encoding of MIME email messages. Review messaging databases for unique message strings ending in one or more “=“ characters.

Other common places where Base64 encoding may exist are in plist files related to applications and configuration profiles loaded to iOS devices and XML files located on Android devices.

References:

[1] https://for585.com/base64decoder1

[2] https://for585.com/base64converter1