Post
Topic
Board Development & Technical Discussion
Re: REWARD offered for hash collisions for SHA1, SHA256, RIPEMD160 and other
by
digaran
on 18/03/2023, 20:17:46 UTC
I hope this act as a heads up for manufacturers, miners, developers, this also could be a known fact, I haven't seen it discussed any where.

Demonstrating two collision attacks in details.

This is a unc public key:
[1]0425f587ba19c90b6e4a6606929bc6a01c44a051805797662ca2cb735dba3c009859f01d2a9e6fa d26fd0fda518271ab0dc32e9a9de6ad3b0f000bd09edfa98ca3
We perform RMD160 on it:
[3]dacb99a98b80d48adbd8b94c9a7905996503d2ab
Result:
[2]1LwtDDHxpvo6Uh9sbRTNSU7r5rukqCFRGC
Now, since there are no SHA-256 hash that long[1] if we find the actual public key of our address[2] and perform a SHA-256 on it, the resulting hash which is a 64 char long hex will produce the same RMD160[3], therefore the SHA-256 of [2]'s actual public key and our fake hash[1] of a public key collide with each other on RMD160 hash function, 2 different inputs with one unchanged output.

Second attempt, this time on SHA-256.

We take this and use it as our public key:

[6]dacb99a98b80d48adbd8b94c9a7905996503d2ab
Then we perform a SHA-256 on it to get our hash of pub ready to convert to an address:
[5]32f51406f6d584a5b62365de425d01f308fc56a33682492284cc7577ceeb8868
Now we do a RMD160 on it:
6c161fcca8bbd0fe7a393b11b0499bb0754e3f7f
And the resulting address is:
[4]1ArWUwF2WfPnDubReohn2vtPodfPpG5Evq

Once again we have arrived at the scene of a collision, if you find the actual public key of [4], and perform a SHA-256 on it, you will see that the result is the same as[5], which means [6] and the actual public key of [4] which are different in value and length etc, collide with a similar SHA-256 hash, 2 different inputs, producing 1 unchanged output.


Do that long enough on too many objects, you will have a collection of collisions, conditionally if you could find the public keys of your generated addresses though.

More over, there are some funded addresses and obviously their owners are unaware that they are holding the key to an actual collision, sooner or later people will figure this out and will exploit it, also the owners of such addresses should transfer their funds to avoid unwanted stalkers, I imagine that top level gov agencies already are aware of this, the reason for publishing this, is to prevent unexpected harm to people and to the entire crypto-system in the future.