0") } prf := hmac.New(h, []byte(password)) hmac.MarkAsUsedInKDF(prf) hashLen := prf.Size() numBlocks := divRoundUp(keyLength, hashLen) const maxBlocks = int64(1<<32 - 1) if keyLength+hashLen < keyLength || int64(numBlocks) > maxBlocks { return nil, errors.New("pbkdf2: keyLength too long") } var buf [4]byte dk := make([]byte, 0, numBlocks*hashLen) U := make([]byte, hashLen) for block := 1; block <= numBlocks; block++ { // N.B.: || means concatenation, ^ means XOR // for each block T_i = U_1 ^ U_2 ^...