[Date Prev][Date Next] [Chronological] [Thread] [Top]

# DIGEST-MD5 and the draft

```                Hello

I've read the draft times and times again, and I have a doubt.
In section 1.1 (Conventions and Notation):

Let { a, b, ... } be the concatenation of the octet strings a, b, ...

Let H(s) be the 16 octet MD5 hash [RFC 1321] of the octet string s.

Let KD(k, s) be H({k, ":", s}), i.e., the 16 octet hash of the string k,
a colon and the string s.

Let HEX(n) be the representation of the 16 octet MD5 hash n as a string
of 32 hex digits (with alphabetic characters always in lower case, since
MD5 is case sensitive).

Then, when it comes to compute the response-value, section
2.1.2.1, page 10:

2.1.2.1   Response-value
The definition of "response-value" above indicates the encoding for its
value -- 32 lower case hex characters. The following definitions show
how the value is computed.

response-value  =
HEX( KD ( HEX(H(A1)),
{ nonce-value, ":" nc-value, ":",
cnonce-value, ":", qop-value, ":", HEX(H(A2))
}))

Okay, so what's the use for KD? As far as I understand:

KD(k, s) = H({k, ":", s})

So, I can compute the response-value as:

HEX( H( { HEX(H(A1)), ":",
nonce-value, ":" nc-value, ":",
cnonce-value, ":", qop-value, ":", HEX(H(A2))

}
))

Is this correct?

Thanks,
Misa

```