https://github.com/xaionaro-go/ecdsakeyderivation
Public key derivator for ECDSA (without knowledge of the private key)
https://github.com/xaionaro-go/ecdsakeyderivation
ecdsa key-derivation
Last synced: 3 months ago
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Public key derivator for ECDSA (without knowledge of the private key)
- Host: GitHub
- URL: https://github.com/xaionaro-go/ecdsakeyderivation
- Owner: xaionaro-go
- License: cc0-1.0
- Created: 2021-12-11T13:27:21.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2021-12-16T10:22:06.000Z (over 3 years ago)
- Last Synced: 2025-01-10T02:44:57.888Z (4 months ago)
- Topics: ecdsa, key-derivation
- Language: Go
- Homepage:
- Size: 8.79 KB
- Stars: 0
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# A proof of concept of a public key derivation for ECDSA (without knowledge of the private key)
WARNING! Do not use this code in production. It was never validated by a real specialist in cryptography.
Also be aware, knowing the child private key and the derivation key is enough to easily restore the parent private key.
# Simple
It is a demonstration of how to implement a simple key derivation algorithm for public keys without knowledge of private keys. This works for any asymmetric crypto algorithm with distributive property enabled for public key. The idea is very simple:
Let's imagine `s0` is the private key, then public key would be `P0 = s0*B` (where `B` is the basepoint of the curve). So if a new private key is derived as `s1 = s0 + d` then a new public key could be derived as `P1 = s1*B = (s0+d)*B`. Thus new public key is: `P1 = s0*B + d*B = P0 + d*B`. That's it.
# Demonstration
See the unit test:
```go
func TestDerivePublic(t *testing.T) {
randReader := rand.New(rand.NewSource(0))
derivationKey := []byte{1, 2, 3}
privKey, err := ecdsa.GenerateKey(elliptic.P521(), randReader)
require.NoError(t, err)
derivedPubKey := DerivePublic(privKey.Public().(*ecdsa.PublicKey), derivationKey)
derivedPrivKey := DerivePrivate(privKey, derivationKey)
require.NotEqual(t, privKey, derivedPrivKey)
require.Equal(t,
derivedPrivKey.Public().(*ecdsa.PublicKey),
derivedPubKey,
)
}
```
result:
```sh
xaionaro@void:~/go/src/github.com/xaionaro-go/ecdsakeyderivation$ go test ./... -count=1
ok github.com/xaionaro-go/ecdsakeyderivation 0.101s
```