The 32 bytes were just a product of the hash function that we were using,
but I've simplified it by changing the hash function to one that only
generates 8 bytes.
My current solution is:
func EmailToID(email, salt string) int64 {
d := sha3.NewShake256()
d.Write([]byte(email))
d.Write([]byte(salt))
h := make([]byte, 8)
d.Read(h)
var n int64
buff := bytes.NewBuffer(h)
binary.Read(buff, binary.LittleEndian, &n)
if n < 0 {
n *= -1
}
return n
}
So, I'm actually using all 64 bits, but taking the absolute value of the
resulting int64, which in effect means that I'm only considering 63 bytes.
On Saturday, 24 September 2016 02:32:24 UTC+2, Caleb Spare wrote:
>
> You'll probably want to use encoding/binary.
>
> But which 8 of the 32 bytes are you going to use? (or really, which 63
> bits?)
>
> -Caleb
>
> On Fri, Sep 23, 2016 at 5:25 PM, JohnGB <jgbe...@gmail.com <javascript:>>
> wrote:
> > I have a byte slice 32 bytes long, and I would like to use it to
> generate a
> > positive int64. Is there a standard way to do this, or do I need to
> write
> > my own function (most likely using bit shifts)?
> >
> > The backstory is that I need to generate unique (low collision
> likelihood)
> > integer IDs from email addresses. However it needs to be that every
> time a
> > given email is used to generate an int64, that it generates the same
> int64.
> > I've settled on using a SHA3 hash with a salt to get a low collision
> byte
> > slice, which I then need to generate a positive int64 from.
> >
> > --
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