Lattice　attacks　can　compromise　the　security　of　encryption　algorithms　used　in　blockchain　networks,　allowing　attackers　to　tamper　with　transaction　records,　steal　private　keys,　and　execute　other　forms　of　attacks.　With　symmetric　encryption,　both　parties　can　encrypt　and　decrypt　messages　using　the　same　key.　Lattice　attacks　on　digital　signature　algorithms　(ECDSA)　involve　forming　a　basis　and　setting　a　target　vector　from　signatures,　then　solving　the　closest　vector　problem　(CVP)　or　shortest　vector　problem　(SVP)　in　the　generated　lattice　to　obtain　the　private　key.　Prior　research　focused　on　obtaining　leakage　information　from　the　signature＇s　random　nonce　to　facilitate　a　CVP　or　SVP　solution.　This　study　establishes　a　clear　boundary　for　a　successful　ECDSA　attack　and　introduces　a　＂double　basis＂　lattice　version　that　expands　the　boundary　or　reduces　the　necessary　signatures　by　nearly　half　with　the　same　lattice　rank.　To　approach　the　boundary,　a　heuristic　strategy　is　employed　to　shift　the　target　vector　in　different　directions　with　a　feasible　step　size,　using　tests　on　the　Trusted　Platform　Module　(TPM)　2.0　ECDSA.　The　distance　from　the　closest　moved　target　vector　to　the　boundary　is　reduced　by　a　ratio　of　424　to　179　to　the　minimal　length　of　orthogonal　vectors　in　the　formed　basis.　Experimental　results　show　that　moving　attempts　in　two　directions　with　the　original　basis　and　84　signatures　take　approximately　247.7　s　on　the　experiment　computer.