Encrypt message text friendly

Question

I have a simple class to make encryption/decryption of string data using a cipher. However, when looking at the crypted text, it's all a bunch of cryptic characters:
Original string: Hello World!
Crypted string: ��?H?�s v���?
The algortihm i'm using is DES provided by javax.crypto. I need to store this text in some email message or other text container and i have problem with certains characters that are not well understood on another machine.
Is there a way to encrypt the string so that it is text friendly, i.e. that it use only letters and numbers to generate the crypted output?
Something like the MIME format.

Answer 1

Not much looked at the different algorithms, but to
what i see they all crypt with blocks of bytes and
don't matter in what range the generated bytes are. Cryptography converts streams of bits into other, essentially randomized, streams of bits. If your crypto is correct, there is no order or range-limitation on the ciphertext.
There must be a way to filter the outputted bytes so
that a call to encrypt with one of a such algorithm
would produce the needed result.Nope - not unless your enciphering algorithm is awful.
Another reason why i'm doing this is to pass encrypted
portions of url into a browser without falling into
illegal characters. I've implemented a way to do it by
converting the generated bytes into hex characters.
It's not much efficient, cause it takes 2 times the
original length of the string, but it works fine for
small strings.Base64 exists precisely to allow for the transfer of random binary data (like ciphertexts) through a text-only medium (like HTTP). The standard procedure is to encrypt- Base64encode - transport - receive - Base64decode - decrypt. Along the way, you can write out your Base64 data and read it, since by definition is consists only of readable characters.
It will, as floersh notes, enlarge your data by 4/3s along the way.
Good luck!
Grant