Base64 is a freeware way of encoding 8-bit characters usingonly ASCII printable characters similar to UUENCODE.UUENCODE embeds a filename where BASE64 does not. You willsee BASE64 used in encoding digital certificates, inencoding user:password string in an Authorization: headerfor HTTP. The spec is described in RFC 2045.For more details see http://mindprod.com/jgloss/base64.htmlDon't confuse Base64 with x-www-form-urlencoded whichis handled by java.net.URLEncoder.encode/decode orBase64u.Base64 armouring uses only the characters A-Z a-z 0-9 +/=.This makes it suitable for encoding binary data as SQLstrings, that will work no matter what the encoding.Unfortunately + / and = all have special meaning in URLs.Base64u gets around this problem. It is a variant on Base64that uses - _ and * in preference to + / and =, so that itcan be used in URLEncoded contexts with or withoutURLEncoding.Use base64 like this:// Base64 armouringimport com.mindprod.base64.Base64;...// sample byte array to encodebyte[] toSend = { (byte)0xfc, (byte)0x0f, (byte)0xc0};// create encoder objectBase64 base64 = new Base64();base64.setLineLength( 72 ); // default// encoding a byte[]String send = base64.encoder( toSend );// decoding a byte[]byte[] reconstituted = base64.decoder( sent );use Base64u the same way:// Base64u armouringimport com.mindprod.base64.Base64u;...// sample byte array to encodebyte[] toSend = { (byte)0xfc, (byte)0x0f, (byte)0xc0};// create encoder objectBase64u base64u = new Base64u();base64u.setLineLength( 72 ); // default// encoding a byte[]String send = base64u.encoder( toSend );// decoding a byte[]byte[] reconstituted = base64u.decoder( sent );For an example that starts and ends with a String, seeExample.javato run:java.exe com.mindprod.base64.Example