MATHEMATICA IMPORT/EXPORT FORMAT

Base64 (.b64)

Base64 binary to text encoding.
Encodes binary data as a sequence of printable ASCII characters.
Commonly used for the transfer of binary content by email.
The Base64 encoding is described in internet standard recommendations RFC 1421 and 2045.
ASCII format.
Uses the 52 uppercase and lowercase letters of the Roman alphabet, the numerals 0 to 9, and the characters

and

to form a positional numeral system using a base of 64.
The

character is used for padding Base64-encoded data.

Import and Export support Base64 encoding.

Import and Export Import and Export

Import["file.ext.b64"] imports a Base64-encoded .ext file.
Export["file.ext.b64", expr] exports an expression to a Base64-encoded .ext file.
Import["file.b64"] decodes a Base64-encoded file and imports its contents as an expression, automatically inferring the format from the file contents.
The import format can be given explicitly with Import["file", {"Base64", "format"}].
Import["file.ext.b64", elem] imports the specified element from a Base64-encoded .ext file.
Import["file.ext.b64", {elem, sub_a, sub_b, ...}] imports a subelement.
Import["file.ext.b64", {{elem₁, elem₂, ...}}] imports multiple elements.
The import format and file encoding can be explicitly specified with Import["file", {"Base64", "format", elems₁, elems₂, ...}].
Export["file.ext.b64", expr, elem] creates a Base64-encoded .ext file by treating expr as specifying element elem.
Export["file.ext.b64", {expr₁, expr₂, ...}, {{elem₁, elem₂, ...}}] treats each as specifying the corresponding .
Export["file.ext.b64", expr, opt₁->val₁, ...] exports expr with the specified option elements taken to have the specified values.
Export["file.ext.b64", {elem₁->expr₁, elem₂->expr₂, ...}, "Rules"] uses rules to specify the elements to be exported.
The export format and file encoding can be explicitly specified with Export["file", exprs, {"Base64", "format", elems}].
See the reference pages for full general information on Import and Export.
ImportString and ExportString support Base64 encoding.