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I want to save a Key in Mysql as String

 
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Guest
PostPosted: Thu May 03, 2007 12:55 am    Post subject: I want to save a Key in Mysql as String Reply with quote


ok
so I'm trying to store a key for late for later use with a password
and i can get as far as saving and retrieving it. but can't use it
again
this is what i have:

KeyGenerator kg = KeyGenerator.getInstance("DES");
Key key = kg.generateKey();
Cipher cipher = Cipher.getInstance("DES");

cipher.init(Cipher.ENCRYPT_MODE,key);
byte[] encrypted_password = cipher.doFinal(password.getBytes());
JOptionPane.showMessageDialog(null,"Encrypted Password "+ new
String(encrypted_password));

String coughtPassword = new String(encrypted_password);

cipher.init(Cipher.WRAP_MODE,key);
byte[] keyAsByte = cipher.wrap(key);
String keyAsString = new String(keyAsByte);

//coughtpassword and keyAsString are save in mySql by a Dao

// the piece i have been unable to do is here i want to reconstruct
keyAsString into the workable key2
//any suggestions are welcome

cipher.init(Cipher.DECRYPT_MODE,key2);
byte[] decrypted_password2 =
cipher.doFinal(coughtPassword.getBytes());
JOptionPane.showMessageDialog(null,"Decrypted Password "+new
String(decrypted_password2));
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x x
Guest
PostPosted: Fri May 04, 2007 7:12 am    Post subject: Re: I want to save a Key in Mysql as String Reply with quote


Never convert the binary byte[] (encrypted_password) into String.

You can use key.getEncoded() which prints an encoded string. Save it in the
database.

When you read the string, you can create the keyspecification using
EncodedKeySpec(byte[] encodedKey)
And Then, use SecretKeyFactory.generateSecret(KeySpec .....) to derive at
the Key.


Thanks,
Selva-
InfoTekies Corporation.



<iszekeell (AT) gmail (DOT) com> wrote in message
news:1178135700.773704.281480 (AT) l77g2000hsb (DOT) googlegroups.com...
Quote:
ok
so I'm trying to store a key for late for later use with a password
and i can get as far as saving and retrieving it. but can't use it
again
this is what i have:

KeyGenerator kg = KeyGenerator.getInstance("DES");
Key key = kg.generateKey();
Cipher cipher = Cipher.getInstance("DES");

cipher.init(Cipher.ENCRYPT_MODE,key);
byte[] encrypted_password = cipher.doFinal(password.getBytes());
JOptionPane.showMessageDialog(null,"Encrypted Password "+ new
String(encrypted_password));

String coughtPassword = new String(encrypted_password);

cipher.init(Cipher.WRAP_MODE,key);
byte[] keyAsByte = cipher.wrap(key);
String keyAsString = new String(keyAsByte);

//coughtpassword and keyAsString are save in mySql by a Dao

// the piece i have been unable to do is here i want to reconstruct
keyAsString into the workable key2
//any suggestions are welcome

cipher.init(Cipher.DECRYPT_MODE,key2);
byte[] decrypted_password2 =
cipher.doFinal(coughtPassword.getBytes());
JOptionPane.showMessageDialog(null,"Decrypted Password "+new
String(decrypted_password2));
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Mike Amling
Guest
PostPosted: Sat May 05, 2007 2:32 am    Post subject: Re: I want to save a Key in Mysql as String Reply with quote


iszekeell (AT) gmail (DOT) com wrote:
Quote:
ok
so I'm trying to store a key for late for later use with a password
and i can get as far as saving and retrieving it. but can't use it
again
this is what i have:

KeyGenerator kg = KeyGenerator.getInstance("DES");
Key key = kg.generateKey();
Cipher cipher = Cipher.getInstance("DES");

cipher.init(Cipher.ENCRYPT_MODE,key);
byte[] encrypted_password = cipher.doFinal(password.getBytes());
JOptionPane.showMessageDialog(null,"Encrypted Password "+ new
String(encrypted_password));

What makes you think that encrypted_password is a legitimate encoding
of characters using the default character encoding?

Quote:
String coughtPassword = new String(encrypted_password);

cipher.init(Cipher.WRAP_MODE,key);
byte[] keyAsByte = cipher.wrap(key);
String keyAsString = new String(keyAsByte);

What makes you think that encrypted_password is a legitimate encoding
of characters using the default character encoding?

Somebody did not read
http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html, which
says "public String(byte[] bytes) ... The behavior of this constructor
when the given bytes are not valid in the default charset is
unspecified." That has always been true, and has been documented since
Java 1.4.

If you want to store arbitrary bytes as a String of characters, you
can convert them to hexadecimal:
final char[] keyAsHex=new char[keyAsBytes.length*2];
for (int jj=keyAsBytes.length, xx=keyAsHex.length; --jj>=0; ) {
final int oneByte=keyAsBytes[jj];
keyAsHex[--xx]="0123456789ABCDEF".charAt(oneByte & 0x0F);
keyAsHex[--xx]="0123456789ABCDEF".charAt((oneByte>>4) & 0x0F);
}
final String keyAsString=new String(keyAsHex);

Quote:
//coughtpassword and keyAsString are save in mySql by a Dao

// the piece i have been unable to do is here i want to reconstruct
keyAsString into the workable key2
//any suggestions are welcome

cipher.init(Cipher.DECRYPT_MODE,key2);
byte[] decrypted_password2 =
cipher.doFinal(coughtPassword.getBytes());
JOptionPane.showMessageDialog(null,"Decrypted Password "+new
String(decrypted_password2));
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Guest
PostPosted: Wed May 09, 2007 10:55 pm    Post subject: Re: I want to save a Key in Mysql as String Reply with quote
thanks man didn't know that bout string and thanks for showing me how
to store a Byte array as a String
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Mike Amling
Guest
PostPosted: Thu May 10, 2007 11:32 pm    Post subject: Re: I want to save a Key in Mysql as String Reply with quote
iszekeell (AT) gmail (DOT) com wrote:
Quote:
thanks man didn't know that bout string and thanks for showing me how
to store a Byte array as a String

You're welcome. Converting back is easy, too. If you know that keyHex
contains an even number of hexadecimal digits (0..9, A..F), then

String keyHex=...
byte[] keyBytes=new byte[keyHex.length()/2];
for (int jb=0, jh=0; jb<keyBytes.length; ++jb) {
keyBytes[jb]=
(("0123456789ABCDEF".pos(keyHex.charAt(jh++)) & 0x0F))<<4)+
("0123456789ABCDEF".pos(keyHex.charAt(jh++)) & 0x0F);
}

--Mike Amling
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Guest
PostPosted: Fri May 11, 2007 12:58 am    Post subject: Re: I want to save a Key in Mysql as String Reply with quote
kool thanks again,
i was wondering would you know of good reading material for
encryption in java. i have only started looking at encryption and it's
causing my more than one headache, like that byte[] to String section,
i'm going to try it with Blob as well think it might be simpler, but i
be really greatful if you could point me in the right direction in
relation to books thanks again!
Michael(Ben)
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Guest
PostPosted: Fri May 11, 2007 1:06 am    Post subject: Re: I want to save a Key in Mysql as String Reply with quote
x x
thank you very much for all your help it really helped with my
encrypion problems, still I just too much of a noob to encryption
thanks so much tho.
could to tell me how to construct a SecretKeyFactory (can't get my
head round provider class) or a link for such. thanks again
Michael(Ben)
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Mike Amling
Guest
PostPosted: Fri May 11, 2007 4:05 am    Post subject: Re: I want to save a Key in Mysql as String Reply with quote
Mike Amling wrote:
Quote:
iszekeell (AT) gmail (DOT) com wrote:
thanks man didn't know that bout string and thanks for showing me how
to store a Byte array as a String

You're welcome. Converting back is easy, too. If you know that keyHex
contains an even number of hexadecimal digits (0..9, A..F), then

String keyHex=...
byte[] keyBytes=new byte[keyHex.length()/2];
for (int jb=0, jh=0; jb<keyBytes.length; ++jb) {
keyBytes[jb]=
(("0123456789ABCDEF".pos(keyHex.charAt(jh++)) & 0x0F))<<4)+
("0123456789ABCDEF".pos(keyHex.charAt(jh++)) & 0x0F);
}

Hmm... The &0x0F is superfluous, it needs a cast and to use indexOf.

String keyHex=...
byte[] keyBytes=new byte[keyHex.length()/2];
for (int jb=0, jh=0; jb<keyBytes.length; ++jb) {
keyBytes[jb]=(byte)(
("0123456789ABCDEF".indexOf(keyHex.charAt(jh++))<<4)+
"0123456789ABCDEF".indexOf(keyHex.charAt(jh++)));
}

--Mike Amling
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