Re: [openpgp] SHA3 algorithm ids.

What is the rationale to implement all sha3 variants?

I understand some protocols need lower grade versions for performance reasons but that seems to matter a lot less for openpgp usage. Why not just implement sha3-512?

Sent from my iPhone

> On Aug 8, 2015, at 11:21, Werner Koch <wk@gnupg.org> wrote:
> 
> Hi!
> 
> Now that an official SHA3 specs has been published I would like to see
> algorithm ids assigned.  Although it is some time until we can publish
> rfc-4880bis, it would be useful to agree on the algorithm ids now.
> This would be helpful for experimental implementations.  Thus what about
> this new table with the SHA2 drop in replacements:
> 
>      ID           Algorithm                             Text Name
>      --           ---------                             ---------
>      1          - MD5 [HAC]                             "MD5"
>      2          - SHA-1 [FIPS180]                       "SHA1"
>      3          - RIPE-MD/160 [HAC]                     "RIPEMD160"
>      4          - Reserved
>      5          - Reserved
>      6          - Reserved
>      7          - Reserved
>      8          - SHA256 [FIPS180]                      "SHA256"
>      9          - SHA384 [FIPS180]                      "SHA384"
>      10         - SHA512 [FIPS180]                      "SHA512"
>      11         - SHA224 [FIPS180]                      "SHA224"
>      12         - SHA3-224 [FIPS202]                    "SHA3-224"
>      13         - SHA3-256 [FIPS202]                    "SHA3-256"
>      14         - SHA3-384 [FIPS202]                    "SHA3-384"
>      15         - SHA3-512 [FIPS202]                    "SHA3-512"
>      100 to 110 - Private/Experimental algorithm
> 
> Note that I ordered SHA3-224 first; when we did SHA2 we forgot about 224
> and thus it ended up out of order.
> 
> I am not sure about the text name.  Is a dash okay (cf. armor header)?
> 
> The OIDS are:
> 
>   The hexadecimal representations for the
>   currently defined hash algorithms are as follows:
> 
>     [...]  
> 
>     - SHA3-224:   0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x07
>     - SHA3-256:   0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x08
>     - SHA3-384:   0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x09
>     - SHA3-512:   0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x0a
> 
>   The ASN.1 Object Identifiers (OIDs) are as follows:
> 
>     [...]
> 
>     - SHA3-224:   2.16.840.1.101.3.4.2.7
>     - SHA3-256:   2.16.840.1.101.3.4.2.8
>     - SHA3-384:   2.16.840.1.101.3.4.2.9
>     - SHA3-512:   2.16.840.1.101.3.4.2.10
> 
>   The full hash prefixes for these are as follows:
> 
>       [...]
> 
>       SHA3-224:   0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
>                   0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x07, 0x05,
>                   0x00, 0x04, 0x40
> 
>       SHA3-256:   0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
>                   0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x07, 0x05,
>                   0x00, 0x04, 0x40
> 
>       SHA3-384:   0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
>                   0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x07, 0x05,
>                   0x00, 0x04, 0x40
> 
>       SHA3-512:   0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
>                   0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x07, 0x05,
>                   0x00, 0x04, 0x40
> 
> 
> 
> Shalom-Salam,
> 
>   Werner
> 
> 
> -- 
> Die Gedanken sind frei.  Ausnahmen regelt ein Bundesgesetz.
> 
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