Hello Thomas, et al.,
On 3/26/2018 1:49 PM, Jamil Nimeh wrote:
Hi Thomas, thanks for the feedback
1. Were there guidelines? Not really, though I looked at other
parameter definitions in com.sun.crypto.provider and tried to
follow along the same lines that they do. One thing that should
be changed is the LINE_SEP assignment shouldn't be an explicit
getProperty call. I noticed most are doing System.lineSeparator()
so I'll change my implementation to match that. None of these
params appear to stringify as json, so I'll probably keep things
consistent with the other parameter output.
2. You make a fair point with respect to a null SecureRandom. I can
make that spec change.
3. Let me think on this one - I shied away from ChaCha20ParameterSpec
for AEAD mode only because you have this nonce field that is set
but gets ignored. But making ChaCha20ParameterSpec an
IvParameterSpec potentially runs into the same issue were it used
for a ChaCha20-Poly1305 cipher. If I had to choose between the two
I think I'd go with allowing ChaCha20ParameterSpec to be used with
CC20-P1305 rather than making it a subclass of IvParameterSpec.
Doing the former helps from a type safety perspective that you
couldn't use a ChaCha20ParameterSpec with other Ciphers that
require an IvParameterSpec. I know I had some discussions early
on in the design where we talked about this, I need to refresh my
memory as to why we didn't allow it.
Finally getting back to #3. Took me a while to find early discussions
on this. The primary objection to ChaCha20ParameterSpec being used with
ChaCha20-Poly1305 (as opposed to plain old ChaCha20) has to do with the
configurable block counter. You have this parameter that is not used,
and consumption of this type of AlgorithmParameterSpec then leaves it to
documentation to define what happens (is it ignored? Used despite what
the spec says? Set to some default value regardless of what the caller
sets there?). Using IvParameterSpec with ChaCha20-Poly1305 is more clear
because it only allows the caller what they need to get CC20/P1305
going, the nonce. Respectfully, I would like to keep this as-is.
--Jamil
On 3/26/2018 12:45 PM, Thomas Lußnig wrote:
Hi Jamil,
1) where there any guidelines about how the engineToString should be
formatted ?
I ask because i wondering why we need two new lines with access to
the System property.
If it is represented as single line json no need to line break would
be needed.
Gruß Thomas
/** * Creates a formatted string describing the parameters. * *
@return a string representation of the ChaCha20 parameters. */
@Override protected String engineToString() { String LINE_SEP =
System.getProperty("line.separator"); HexDumpEncoder encoder = new
HexDumpEncoder(); StringBuilder sb = new StringBuilder(LINE_SEP +
"nonce:" + LINE_SEP + "[" + encoder.encodeBuffer(nonce) + "]");
return sb.toString(); }
2) I do not think it is an good idea to say no secureRandom=null will cause IV
to be null.
I see here the risk of weak implementations. I would suggest to throw an
Exception to
enforce secure usages. If someone really want an insecure IV he can provide
am SecureRandom
implementation retuning 0 only or an matching IV.
* @param random a {@code SecureRandom} implementation. If {@code null}
* is used for the random object, then a nonce consisting of all
* zero bytes will be used. Otherwise a random nonce will be
* used.
3) If ChaCha20ParameterSpec would extends IvParameterSpec if would be valid for
booth modes in engineInit.
Even if the counter is not needed.
As an alternative i would allow ChaCha20ParameterSpec also for AEAD mode.
Grup Thomas
On 3/26/2018 9:08 PM, Jamil Nimeh wrote:
Hello all,
This is a request for review for the ChaCha20 and ChaCha20-Poly1305
cipher implementations. Links to the webrev and the JEP which
outlines the characteristics and behavior of the ciphers are listed
below.
http://cr.openjdk.java.net/~jnimeh/reviews/8153028/webrev.01/
http://openjdk.java.net/jeps/329
Thanks,
--Jamil
