On Wed, Dec 23, 2015 at 2:19 PM, Christian Huitema <huit...@microsoft.com> wrote:
> In the current 1.3 draft, section 6.3.4.3 specifies the content of the > Finished message. It contains this specification for key computation: > > client_finished_key = > HKDF-Expand-Label(BaseKey, "client finished", "", L) > > server_finished_key = > HKDF-Expand-Label(BaseKey, "server finished", "", L) > > I wonder what the zero length string actually means. Is it a > null-terminated string that would encode in binary as a one octet byte > string of value 0, or an empty string that would encode in binary as a zero > length string? > I see what you mean about the ambiguity here. What I meant was 0 bytes (i.e., no trailing '\0'). There is one example of encoding a string in section 4.8.1, and the binary > representation shows the encoding of the final null byte. Is that a common > assumption? > No. > Similarly, in the HKDF-Expand-Label, do we assume a final null byte for > the "label"? > No. I wonder if we should instead add the '\0' explicitly in the 4.8.1 for maximal clarity. -Ekr > -- Christian Huitema > > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls >
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