im trying to build something in cardano, and i want to check if policy id provided by the user is an actual policyid? after research i found that blake2b_224 is used for hashing the policy id,is there away to validate that a string was blake2b_224 hashed
Is there a way to validate a policy Id,and to check if a string is an actual policy id?
Depending on your usecase... If you just need to know it exists, then you can scan the chain (db-sync, chain-index, blockfrost,...)
If you need to verify it against a minting policy, you'll obvs need access to that too and do the hashing like what KtoZ says. There are however resources listing currency symbols. (TBC, but) CardanoScan records and verifies native scripts (not plutus atm)
Beyond the length of the hash digest (28 bytes in this case), no. Unless you have the pre-image (that is, the raw policy script) in which case you can rehash it and compare.