> For the complete documentation index, see [llms.txt](https://docs.xenblocks.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.xenblocks.io/technicals/hashing/self-custodial-hashing.md).
# Self-custodial hashing
In most Proof of Work (PoW) systems, there are primarily two critical elements: the key and the hash. A vulnerability in such systems is the potential for someone to intercept mined blocks before they are verified and accepted by the blockchain. This interception could allow an attacker to reroute blocks without the ability to change the owner's address, simplifying the process of executing attacks on the chain by reordering blocks and claiming ownership.
However, such a scenario is not feasible with XenBlocks. In XenBlocks, all mined blocks are cryptographically signed with the miner's Ethereum address, ensuring that block theft is impossible. The only way for someone to take ownership of a block is if the original owner divulges their private key, providing a significant layer of security against block interception and unauthorized ownership changes.
Miner ETH address is used as SALT input when mining
The Ethereum address is efficiently compacted into 27 bytes, which is quite minimal. Subsequently, the discovery of a hashed block is attributed to the address, signified by the Salt. Thus, when mining, your Ethereum address is utilized as the Salt. Unlike Bitcoin, which does not incorporate Salt in its SHA-256 algorithm, Argon2 does implement this feature, allowing for this added layer of association between mined blocks and the miner's address.
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