/
verifier.go
57 lines (47 loc) · 1.49 KB
/
verifier.go
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package wallet
import (
"bytes"
"crypto/ed25519"
"crypto/sha256"
"errors"
"github.com/bartossh/Computantis/serializer"
)
// Helper provides wallet helper functionalities without knowing about wallet private and public keys.
type Helper struct{}
// NewVerifier creates new wallet Helper verifier.
func NewVerifier() Helper {
return Helper{}
}
// AddressToPubKey creates ED25519 public key from address, or returns error otherwise.
func (h Helper) AddressToPubKey(address string) (ed25519.PublicKey, error) {
pubKey, err := serializer.Base58Decode([]byte(address))
if err != nil {
return []byte{}, err
}
if len(pubKey)-checksumLength < 1 {
return []byte{}, errors.New("address of invalid length")
}
actualChecksum := pubKey[len(pubKey)-checksumLength:]
version := pubKey[0]
pubKey = pubKey[1 : len(pubKey)-checksumLength]
targetChecksum := checksum(append([]byte{version}, pubKey...))
if !bytes.Equal(actualChecksum, targetChecksum) {
return []byte{}, errors.New("address checksum is not equal")
}
return pubKey, nil
}
// Verify verifies if message is signed by given key and hash is equal.
func (h Helper) Verify(message, signature []byte, hash [32]byte, address string) error {
digest := sha256.Sum256(message)
if !bytes.Equal(hash[:], digest[:]) {
return errors.New("hash is corrupted")
}
pubKey, err := h.AddressToPubKey(address)
if err != nil {
return err
}
if !ed25519.Verify(pubKey, digest[:], signature) {
return errors.New("message signature isn't valid")
}
return nil
}