71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
package blob
|
|
|
|
import (
|
|
"crypto/sha256"
|
|
"encoding/hex"
|
|
|
|
"github.com/btcsuite/btcd/chaincfg/chainhash"
|
|
)
|
|
|
|
// BreachHintSize is the length of the identifier used to detect remote
|
|
// commitment broadcasts.
|
|
const BreachHintSize = 16
|
|
|
|
// BreachHint is the first 16-bytes of SHA256(txid), which is used to identify
|
|
// the breach transaction.
|
|
type BreachHint [BreachHintSize]byte
|
|
|
|
// NewBreachHintFromHash creates a breach hint from a transaction ID.
|
|
func NewBreachHintFromHash(hash *chainhash.Hash) BreachHint {
|
|
h := sha256.New()
|
|
h.Write(hash[:])
|
|
|
|
var hint BreachHint
|
|
copy(hint[:], h.Sum(nil))
|
|
return hint
|
|
}
|
|
|
|
// String returns a hex encoding of the breach hint.
|
|
func (h BreachHint) String() string {
|
|
return hex.EncodeToString(h[:])
|
|
}
|
|
|
|
// BreachKey is computed as SHA256(txid || txid), which produces the key for
|
|
// decrypting a client's encrypted blobs.
|
|
type BreachKey [KeySize]byte
|
|
|
|
// NewBreachKeyFromHash creates a breach key from a transaction ID.
|
|
func NewBreachKeyFromHash(hash *chainhash.Hash) BreachKey {
|
|
h := sha256.New()
|
|
h.Write(hash[:])
|
|
h.Write(hash[:])
|
|
|
|
var key BreachKey
|
|
copy(key[:], h.Sum(nil))
|
|
return key
|
|
}
|
|
|
|
// String returns a hex encoding of the breach key.
|
|
func (k BreachKey) String() string {
|
|
return hex.EncodeToString(k[:])
|
|
}
|
|
|
|
// NewBreachHintAndKeyFromHash derives a BreachHint and BreachKey from a given
|
|
// txid in a single pass. The hint and key are computed as:
|
|
// hint = SHA256(txid)
|
|
// key = SHA256(txid || txid)
|
|
func NewBreachHintAndKeyFromHash(hash *chainhash.Hash) (BreachHint, BreachKey) {
|
|
var (
|
|
hint BreachHint
|
|
key BreachKey
|
|
)
|
|
|
|
h := sha256.New()
|
|
h.Write(hash[:])
|
|
copy(hint[:], h.Sum(nil))
|
|
h.Write(hash[:])
|
|
copy(key[:], h.Sum(nil))
|
|
|
|
return hint, key
|
|
}
|