1. Blockchain Concepts RISK FORUM 2017 Hash function (e.g. SHA-256)
User A
Header Block #N+1
Nonce
Transactions …
N+1 ?
N+1 ?
Node Y
B#N
Node X
B#N
Header Block #N … …
Nonce
Transactions …
B#1
B#1
B#0
B#0
Cryptographic linkage
(using a hash function…)
providing security…
Blockchain copy on X
Blockchain copy on Y
User B
If user A transacts with B, how is the transaction validated ?
It the P2P network open to public or not ? Yes for Bitcoin or Ethereum, no for (semi-)private/consortium chains…
How is consensus achieved / which protocol ? Proof-of-Work (PoW), Proof-of-Stake (PoS),…
Is data on the blockchain visible to all ? Yes for Bitcoin ; not necessarily for a private network…
Do I know the user behind a public address ? Usually not, it’s pseudonymous… Different if access is permissioned… ….