Quote from: Salam22 on Today at 09:49:24 AM

I recently joined this fantastic community and read up on the bitcoin blockchain and other topics related to bitcoin. As a result, I have a few questions to ask.
1 What distinguishes a soft fork from a hard fork in the context of blockchain technology?
2 What is the cryptographic algorithm that protects the blockchain of the Bitcoin?
3 What is the maximum quantity of transactions that can be recorded on the Bitcoin blockchain in a single block?

1. A soft fork is backwards compatible... Basically, older nodes can still accept and validate post-fork blocks. For example, when segwit was introduced, the 1Mb block size was kept, the "real" transaction data was all included in the first 1Mb of the block, 3Mb was added, but only for witness data. Old pre-fork nodes could still read and validate all transaction data which was constructed in such a way it was still valid data for pre-fork nodes. Post-fork nodes could read the transaction data AND the witness data, and they could use this info to validate transactions aswell.

2. sha256d

3. 1 Mb of "real" transaction data + 3 Mb of witness data...