.net - Hash on Unicode Password -

i'm writing password salt/hash procedure .net application, largely following guide of article: http://www.aspheute.com/english/20040105.asp

basically code computing salted hash this:

public string computesaltedhash(string password, byte[] salt) {      // password ascii text bytes:     byte[] passwordbytes = system.text.encoding.ascii.getbytes(password);      // append 2 arrays     byte[] tohash = new byte[passwordbytes.length + salt.length];     array.copy(passwordbytes, 0, tohash, 0, passwordbytes.length);     array.copy(salt, 0, tohash, passwordbytes.length, salt.length);      byte[] computedhash = sha1.create().computehash(tohash);      // return ascii string     return system.text.encoding.ascii.getstring(computedhash); } 

however, want allow allow users use unicode chars in password, if like. (this seems idea; can think of reason it's not?)

however, don't know ton how unicode works, , i'm worried if change both references of system.text.encoding.ascii system.text.encoding.unicode, hash algorithm might produce byte combinations don't form valid unicode chars , getstring call freak out.

is valid concern, or ok?

you shouldn't using any normal encoding convert arbitrary binary data string. it's not encoded text - it's sequence of bytes. don't try interpret if "normal" text. whether original password contains non-ascii characters irrelevant - current code broken. (i treat linked article large dose of suspicion on basis.)

i suggest:

• use encoding.utf8 bytes password. allow password contain unicode character. encoding.unicode fine here too.
• use convert.tobase64string convert computed hash text. base64 designed represent opaque binary data in text within ascii character set.