Ways of Proving Casascius coin authenticity.

[mojolama]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

[mdayonliner]

Suggestions for other methods to authenticate?

I will be following this topic hoping to get some good insights. I always thought to play with coins and collectibles but I have zero Idea how to find the authenticity and also security.

- How do you know in a Casascius coin the private key is not compromised? I hope I did not ask a stupid question  

OP: Thanks for creating the topic.

[krogothmanhattan]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.

Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0

[vizique]

This might be useful to you

https://casascius.uberbills.com/

Viz

[Hellot]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.

Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0

The printing for the public key is another authentication mechanism so blurring it will make authenticating it less certain.  Things like ink pigment and bleeding under magnification should be consistent with your control(known good coins).  The early coins that were inkjet printed right onto the hologram should also match.  As time goes on these aspects of the coin will age and a newer copy would stand out.

[dazedfool]

Just mail them all to me for authentication. I'll be sure to properly dispose of any fakes 

[OgNasty]

Suggestions for other methods to authenticate?

Take a look at some images of fakes and familiarize yourself with the differences.

[krogothmanhattan]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.

Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0

The printing for the public key is another authentication mechanism so blurring it will make authenticating it less certain.  Things like ink pigment and bleeding under magnification should be consistent with your control(known good coins).  The early coins that were inkjet printed right onto the hologram should also match.  As time goes on these aspects of the coin will age and a newer copy would stand out.

That is true and good point.

I was suggesting to blurr the public keys in order to prevent any dusting and also for him to keep public keys private and not be exposed.

[krogothmanhattan]

Suggestions for other methods to authenticate?

Take a look at some images of fakes and familiarize yourself with the differences.

  This thread is an excellent source to compare some pretty good fakes against the real Casascius  https://bitcointalk.org/index.php?topic=3257048.0

[Hellot]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.

Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0

The printing for the public key is another authentication mechanism so blurring it will make authenticating it less certain.  Things like ink pigment and bleeding under magnification should be consistent with your control(known good coins).  The early coins that were inkjet printed right onto the hologram should also match.  As time goes on these aspects of the coin will age and a newer copy would stand out.

That is true and good point. I was asking to blurr to prevent any dusting and also for him to keep pub key private and not be exposed.

I've yet to see a compelling argument that dusting is harmful.  I have even sought out dusted coins for their historical significance like the Sochi Olympics duster.  Not that I would but you can exclude the dust when you redeem it.

[mojolama]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.

Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0

Thanks for offer. Thing is that I'm confident that they are original as got them directly from Mike . It is more to prove authenticity to a buyer and give them confidence when a deal is being done.

[Hellot]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.

Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0

Thanks for offer. Thing is that I'm confident that they are original as got them directly from Mike . It is more to prove authenticity to a buyer and give them confidence when a deal is being done.

If you still have your correspondence from Mike that will help.  It's not proof on its own but it adds to the certainty.

[krogothmanhattan]

As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didn’t think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesn’t have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.

Suggestions for other methods to authenticate?

Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.

Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0

The printing for the public key is another authentication mechanism so blurring it will make authenticating it less certain.  Things like ink pigment and bleeding under magnification should be consistent with your control(known good coins).  The early coins that were inkjet printed right onto the hologram should also match.  As time goes on these aspects of the coin will age and a newer copy would stand out.

That is true and good point. I was asking to blurr to prevent any dusting and also for him to keep pub key private and not be exposed.

I've yet to see a compelling argument that dusting is harmful.  I have even sought out dusted coins for their historical significance like the Sochi Olympics duster.  Not that I would but you can exclude the dust when you redeem it.

I like my Cas coins to be pure at 1btc

But to each his own.

[av8rjeff]

Um....what is "dusting"?   

[anonymousminer]

Um....what is "dusting"?   

Sending a small amount of BTC to the coins

[av8rjeff]

I see.  And so that could have the effect of devaluing the coin?  Or is there some other purpose for the attack?

[krogothmanhattan]

I see.  And so that could have the effect of devaluing the coin?  Or is there some other purpose for the attack?

  If I buy a 1BTC loaded coin I want it at 1BTC not even one Satoshi over. In other words untainted.

[Lauda]

I see.  And so that could have the effect of devaluing the coin?  Or is there some other purpose for the attack?

Yes, to some extent. Many collectors feel that a "X" face value coin should contain that exact amount.
Anything under or over would breach the collectible value plus you also now take into account a coin/amount that was not "maker funded"

Collectors aren't known as the wisest people around here. One way to counter it would be to dust all known addresses that are still funded.

I see.  And so that could have the effect of devaluing the coin?  Or is there some other purpose for the attack?

The purpose of a dusting attack is not devaluing a coin; it's usually either promotion or a privacy attack on UTXO sets.

[jackbauercsgo]

Dusting is a way to connect a wallet to a person.