I would like to store some sensitive data and because the node would be public I am worried that if can be reserved.

What do you suggest to store sensitive data(passwords) in blockchain?


2 Answers 2


Encrypt the data before you supply it to the blockchain using a sufficiently strong encryption algorithm. Alternatively you can leave a reference in the blockchain, which is the suggested approach for data that does not need to be processed within the consensus system. The flow could be:

  1. Encrypt data off-chain
  2. Supply encrypted data off-chain to IPFS
  3. Store IPFS-CID of the encrypted data in the blockchain using an extrinsic.
  • Everything you store in the blockchain is publicly visible to anyone, so you need a way to obfuscate sensitive data in a way that allows only you to see it clearly. Encryption is usually the way to go. Although practically unbreakable ("practically" because it takes too long), at some point in time advancements in technology and research could lead to practically relevant solution to break the encryption. Should this happen, your data can be encrypted and since it stored and replicated on a public ledger, you won't just be able to delete it.
    – sea212
    Commented Jan 29, 2023 at 22:47

Strong cryptographic hash functions are designed to be irreversible. Blake2-128 is quite secure (see the claims on https://www.blake2.net/), and it is fine to post hashes of sensitive data to the blockchain.

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