3

The Ethereum wallet app Blockwallet for iOS generates seed phrases with 24 words (BIP39).

Using their keytools I am able to get a private key.

How do I convert the private key into a 12 word seed phrase that works with Metamask?

migrated from crypto.stackexchange.com Nov 29 '17 at 22:08

This question came from our site for software developers, mathematicians and others interested in cryptography.

  • I found another way to import a private key into Metamask but I'd still like to know how to generate a 12 word seed from a private key. – neuhaus Nov 29 '17 at 14:04
2

You cannot convert a private key into a seed.

The operation of deriving a public or private key from a seed is intentionally irreversible. The idea is to prevent someone who knows one of your public or private keys from discovering others.

  • I think you are mistaken. After all I can generate a 24 word seed from any private key. But if you have something to back it up, please show it. – neuhaus Jun 15 '18 at 8:06
  • 1
    Seeds are converted into private keys by the process detailed in BIP 32 (github.com/bitcoin/bips/blob/master/bip-0032.mediawiki). Several of the steps are in this process are designed to be irreversible. If you have a process that can turn a private key into a 24 word seed (that can then derive the same private key), then I've never heard of it, and would be very interested. – James_pic Jun 15 '18 at 10:25
  • Thanks. Looks like the seed phrase just provides a seed that is run through SHA512 to generate the key, so it can't be reversed. Still, the original question was how to convert a 24 word seed into a 12 word seed, this should be doable. – neuhaus Jul 15 '18 at 18:01
  • Converting a 24 word seed to a 12 word seed is also impossible, but for different reasons. According to BIP 39, a mnemonic seed is converted into a binary seed using PBKDF2-SHA-512. To turn a 24 word seed into a 12 word seed, you'd need to find a 12 word seed that produced the same binary seed as the 24 word seed, which would constitute a seconds preimage attack on PBDKF2-SHA-512, which is believed to be impossible. – James_pic Jul 16 '18 at 11:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.