The Why behind UUencoding and Other Schemes

Some Internet protocols were not designed to carry binary (program and other non-text files) files. They are only able to transfer messages made up of conventional text (printable ASCII) characters. In order to get around that limitation, UUencode and other methods were created.

These solutions all perform the same basic operation: they encode the non-transferable binary file into ASCII characters that the e-mail system can handle. The person receiving the message can then decode the strings of characters to recreate the original file. Perhaps you have seen one of these apparently unintelligible messages; here's an example:

begin 666 encoded.txt
M5&5S="$-"@T*1V5N=&QE(%)E861E<CH-"@T*5&AI<R!I<R!N;W1H:6YG(&UO
M<F4@=&AA;B!A('1E<W0@9FEL92!C<F5A=&5D('1O('!R;W9I9&4@9F]D9&5R
M(&9O<B!T:&4@=F%R:6]U<R!E;F-O9&EN9R!S8VAE;65S+B!)9B!Y;W4@87)E
M('5S:6YG(&ET('1O('1E<W0L(&-O;F=R871U;&%T:6]N<R!O;B!Y;W5R(&%G
M:6QI='D@:6X@8W5T=&EN9RP@<&%S=&EN9RP@<V%V:6YG+"!A;F0@9&5C;V1I
:;F<@=7-I;F<@5VEN6FEP+@T*#0I%;FIO>2$`
`
end