Re: [openpgp] v5 sample key

[Werner Koch <[e-mail]>]

On Thu,  2 May 2019 18:27, [e-mail] said:

> to 4-octet length representation during fingerprint and signature
> calculations is intended to allow for significantly larger keys if there
> are any post-quantum algorithms that need it.

Right, that is the required change to allow the addition of PQ algos to
OpenPGP.

> they're aiming for smallness.  We're only talking about 4 octets in RAM
> when calculating the key fingerprint or the signature, right?

Right.  Snippet from code for fingerprint hashing:

  if (is_v5)
    {
      gcry_md_putc ( md, 0x9a );     /* ctb */
      gcry_md_putc ( md, n >> 24 );  /* 4 byte length header */
      gcry_md_putc ( md, n >> 16 );
      gcry_md_putc ( md, n >>  8 );
      gcry_md_putc ( md, n       );
      gcry_md_putc ( md, pk->version );
    }
  else
    {
      gcry_md_putc ( md, 0x99 );     /* ctb */
      gcry_md_putc ( md, n >> 8 );   /* 2 byte length header */
      gcry_md_putc ( md, n );
      gcry_md_putc ( md, pk->version );
    }


Salam-Shalom,

   Werner

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