Re: [boost] NuDB: A fast key/value insert-only database for SSD drives in C++11

On 27/03/2017 12:21, Vinnie Falco via Boost wrote:

On Mon, Mar 27, 2017 at 6:57 AM, Niall Douglas via Boost wrote:

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The point being made here is that you need to use a high quality secure hash when writing data to storage. That way after power loss you can determine if the database store is truly in a consistent and valid state rather than being tricked into thinking it is, and then unwittingly destroying more user data.

Oh...I misunderstood. The hash function in NuDB is not used to calculate a digest of the value, its used only to determine which bucket to place the key in the hash table. NuDB is essentially an on-disk unordered_map. That is why the hash function does not need to be cryptographically secure.

This is why I was mentioning that to achieve durability, during writes you crypto hash AND fast hash the new item. During lookups you use the fast hash only. The issue I am taking here is the claim of durability which is a very strong guarantee. If you don't claim that, I have no issue. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/