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Is it technically possible to create and use dynamic private key - public key pair and use it with bitcoin?

I am not sure anything conceptually similar to this already exists. Yet, "dynamic" private - public key pair can be defined as ordinary key pair with 2FA capabilities. Both the keys regularly change per generated 2FA token.

Basically I hope the following,

  1. create dynamic private - public key pair, combining 2FA (like, google authenticator) and a passphrase
  2. this key pair can only be used for a short defined duration, or as long as 2FA token is valid
  3. receive funds
  4. chronologically old key pairs can be used to check / receive funds (or, not)
  5. In future, private key generated from passphrase and 2FA token can be used to spend the coins

BIP 38 is not anyway related to this.

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please feel free to edit / comment, if anything is not clear. –  vi.su. Jan 31 '13 at 11:22
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I don't understand the question. In step 2, you say "this key pair can only be used for a short defined duration". Used to do what? –  David Schwartz May 2 '13 at 6:48
    
Can you explain the purpose of "dynamic keys"? –  Eyal May 2 '13 at 7:11
    
@Eyal, I was looking for a way to make spending possible by some combination of private key + two factor authentication (like, google authenticator). I thought, it is possible through script, but I was never able to solve this. –  vi.su. May 3 '13 at 9:54
    
The idea behnd second-factor is that it changes. There are three factors in auth: who you are, what you know, and what you have. "what you know" is password. "who you are" is a fingerprint. "what you have" is maybe a smartphone. But since the password is only ever useful once, because you can only spend once, there's no need for a changing key. –  Eyal May 3 '13 at 15:22
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1 Answer

No, it is not possible to do what you are suggesting. Here's more info about cryptography.


You can create create an ECDSA keypair with almost any random data (it must a lower than a certain value, but go check ECDSA specs) and then generate an address... But a keypair will always be valid to receive bitcoins or send them (if you still have the private key).

The thing is that a other party will not be able to know what is your next address since you need the private key to do that.

So yeah you can create keypairs with almost any data, but I don't think it'll be dynamic in the way you think.

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"The thing is that a other party will not be able to know what is your next address since you need the private key to do that." - this is expected, and this also prevents others from checking my balance. –  vi.su. Feb 1 '13 at 1:22
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