Initializing, please wait a moment

Cach Doc va So Sanh Hash MD5 Dung Cach: Hoa Thuong, Khoang Trang, Dinh Dang Hex

Cap nhat lan cuoi 2026-05-04. Huong dan 30 giay cho thoi diem sau khi ban tao hash tren MD5 Converter (hoac doc duoc tu trang download) va can xac nhan no khop voi gia tri ky vong. Hai hash MD5 hoac la dai dien cho cung mot digest 16 byte hoac khong. Khac biet ve hoa thuong, khoang trang xung quanh, mot byte-order mark vo hinh, hoac dinh dang co dau hai cham la cosmetic - hash van la giong nhau. Mot ky tu hex khac o bat ky vi tri nao, mot tong chieu dai khac, hoac mot ky tu khong-hex la khac biet that su - du lieu vao khong giong nhau.

Quyet dinh trong 30 giay. Hai gia tri MD5 trung nhau khi, sau khi chuyen ca hai ve chu thuong va xoa khoang trang xung quanh, 32 ky tu hex trung nhau theo tung vi tri. Khac biet hinh thuc (van la trung nhau): chu hoa vs chu thuong (`A1B2` va `a1b2` la cung mot hex), khoang trang dau hoac cuoi do copy-paste so y, mot UTF-8 BOM vo hinh o dau khi copy tu file text, va dinh dang co dau hai cham (`a1:b2:c3` vs `a1b2c3`). Khac biet that su (khong trung nhau): bat ky chu hex nao khac, mot tong chieu dai khac (chuoi 40 ky tu la SHA-1, khong phai MD5; 64 ky tu la SHA-256), va bat ky ky tu khong-hex nao (chi `0-9` va `a-f`).

Hash MD5 thuc su la gi

Hash MD5 la dau ra cua mot ham nhan bat ky du lieu vao - mot chuoi text, byte cua file, mot stream tu download - va sinh ra mot digest co dinh 16 byte (128 bit). Cac byte la gia tri canonical: do la cai "MD5" thuc su la. Chuoi hexadecimal 32 ky tu ban thay tren man hinh chi la mot ma hoa de doc cua 16 byte do (moi byte tro thanh hai ky tu hex). Hai nguoi viet co the danh cung 16 byte do la `D41D8CD98F00B204E9800998ECF8427E` (chu hoa) hoac `d41d8cd98f00b204e9800998ecf8427e` (chu thuong) hoac `d4:1d:8c:d9:8f:00:b2:04:e9:80:09:98:ec:f8:42:7e` (cach nhau bang dau hai cham, pho bien o mot so tool cu) va ca ba deu la CUNG hash. Cac byte la giong nhau.

De tao mot MD5 moi de so sanh voi gia tri ky vong da xuat ban, dan text goc vao MD5 Converter: dan chuoi va copy ket qua. Neu du lieu vao la file thay vi chuoi, xem MD5 vs SHA-256 - Khi Nao Hash de quyet dinh tool; quy tac so sanh ben duoi giong nhau theo ca hai huong.

Bon khac biet hinh thuc nhung van trung nhau

Bon khac biet thuong gap o muc man hinh trong giong khong trung nhau nhung dai dien cho cung mot digest 16 byte. Neu ban chi thay nhung khac biet nay, hash trung nhau.

  • Chu hoa vs chu thuong. Hex khong phan biet hoa thuong. `D41D8CD98F00B204E9800998ECF8427E` va `d41d8cd98f00b204e9800998ecf8427e` la cung mot hash. Dang chu thuong la quy uoc canonical duoc da so cong cu hien dai dung, ke ca MD5 Converter mien phi; mot so tool cu (va nhieu ban release notes in giay) dung chu hoa. Chuyen ca hai ve chu thuong truoc khi so sanh.
  • Khoang trang dau hoac cuoi. Mot khoang trang, tab, hoac xuong dong sot lai khi copy cung voi hash thi vo hinh tren man hinh nhung pha vo compare nghiem ngat tung ky tu. Cat dau cuoi truoc khi so sanh.
  • Mot byte-order mark (BOM) vo hinh. Khi hash ky vong duoc xuat ban trong file `.txt` luu duoi dang UTF-8 voi BOM, copy dong dau tien keo theo mot chuoi 3 byte vo hinh (`EF BB BF`) cung voi hash. Compare nhin nhu mot chuoi 35 ky tu so voi mot chuoi 32 ky tu. Luu lai file goc duoi dang UTF-8 khong BOM, hoac xoa 3 byte dau cua chuoi da copy.
  • Byte cach nhau bang dau hai cham hoac khoang trang. Mot so tool cu dinh dang hash thanh `d4:1d:8c:d9:8f:00:b2:04:e9:80:09:98:ec:f8:42:7e` (16 cap byte cach nhau bang dau hai cham) hoac `d4 1d 8c d9 8f 00 b2 04 e9 80 09 98 ec f8 42 7e` (cach nhau bang khoang trang). Xoa dau cach va hex 32 ky tu ben duoi la cung mot hash.

Ba dau hieu du lieu vao khong giong nhau

Neu sau khi lam sach phia tren ma chuoi van khac, du lieu vao khong giong nhau. Hai hash duoc tinh tren cac byte khac nhau.

  • Bat ky chu hex nao khac. MD5 co tinh chat avalanche: mot khac biet 1 bit trong du lieu vao thuong lat khoang nua so bit dau ra. Vi vay ngay ca mot ky tu hex khac o bat ky vi tri nao trong chuoi 32 ky tu cung co nghia du lieu vao khong giong nhau. Khong co khai niem "gan giong" cho hash - hoac moi ky tu trung (sau khi lam sach o tren) hoac du lieu vao da khac nhau.
  • Tong chieu dai khac sau khi lam sach. Digest hex MD5 chinh xac 32 ky tu. Chieu dai khac nghia la thuat toan khac: chuoi hex 40 ky tu la SHA-1; 64 ky tu la SHA-256; 8 ky tu la CRC32 (thuong hien thi o he thap phan, khong hex). Neu "MD5 ky vong" cua ban co 40 hoac 64 ky tu, nguoi xuat ban dung thuat toan khac va ban can tool khac.
  • Ky tu khong-hex. Hex MD5 chi chua `0-9` va `a-f` (hoac `A-F`). Mot `g`, `h`, `z`, hoac bat ky chu cai nao khac sau `f` khong phai chu hex MD5. Nguyen nhan thuong gap nhat la chuoi do la base64 (`/=+` va dai chu rong hon) hoac base32 (`a-z` va `2-7`) - mot cach ma hoa khac cua cung 16 byte, nhung quy tac so sanh khi do khac (trong base64 chu hoa thuong van quan trong).

Luong so sanh 5 buoc

Cho ca hai hash qua cung 5 buoc va viec so sanh tro nen co hoc.

  1. Chuyen ca hai chuoi ve chu thuong. Buoc nay xoa khac biet hoa-thuong trong hex.
  2. Cat khoang trang dau va cuoi. Buoc nay xoa khac biet ve khoang trang xung quanh.
  3. Bo dau cach. Xoa moi `:`, ` ` (khoang trang), `-`, hoac ky tu khong-hex khac. Ket qua phai la mot chuoi 32 ky tu chu hex don nhat.
  4. Xac nhan chieu dai la 32 va cac ky tu deu nam trong `0-9 a-f`. Neu mot trong hai phia khong qua kiem tra nay, ban dang so sanh thu khong phai digest hex MD5 (hoac van con o nhiem BOM / ky tu vo hinh; dan chuoi vao hex inspector de phat hien).
  5. So sanh tung ky tu. Neu buoc 1-4 cho ra hai chuoi hex 32 ky tu giong het, hash trung nhau - 16 byte ben duoi la giong nhau va du lieu vao la giong nhau. Neu khac nhau o bat ky vi tri nao, du lieu vao khac nhau.

Khi nao MD5 du - va khi nao khong du

MD5 phu hop cho kiem tra hu hong ngau nhien khi khong co ke thu: xac nhan download ket thuc khong bi bit-rot khi nguoi xuat ban dang ky vong MD5 cung file; xac minh chuyen file cua dong nghiep so voi MD5 ho gui trong cung email. Xac suat hai file khong lien quan tao ra cung mot MD5 ngau nhien la nho khong dang ke. Vi vay neu ban tao hash tren MD5 Converter va no trung voi gia tri xuat ban sau luong 5 buoc, file la file nguoi xuat ban muon.

MD5 KHONG phu hop cho truong hop doi khang - luu mat khau, chu ky bao mat, chong gia mao. Cac nha nghien cuu hien tao ra hai file khac nhau cung mot MD5 trong vai giay tren phan cung thong thuong. Voi nhung truong hop do, tool dung la thuat toan khac. Xem MD5 vs SHA-256 - Khi Nao Hash de quyet dinh thuat toan, Cac Lua Chon Thay The MD5 - bcrypt vs Argon2id vs SHA-256 cho cau tra loi hien dai ve luu mat khau, va Tai Sao MD5 Khong The Giai Ma cho cau hoi lien quan "toi co mot MD5 va muon text goc".

"Gan trung" khong ton tai voi MD5

Huong dan khong khang dinh rang hash co the "gan trung". Hai hash MD5 hoac trung nhau chinh xac sau khi chuan hoa hoa-thuong va khoang trang, hoac khong. Cach hieu cam "hash co le dung vi trong gan giong nhau" khong ap dung cho MD5: hash hoac trung nhau chinh xac theo quy tac chuan hoa hoac khong.

Tinh chat avalanche cua ham hash khien dam bao nay tro thanh co hoc: mot thay doi 1 bit trong du lieu vao lat khoang nua so bit dau ra, nen mot gan-trung trong hash khong bao gio tuong duong gan-trung trong du lieu vao. Neu hash cua ban tu MD5 Converter khac voi gia tri ky vong xuat ban o bat ky chu hex nao, byte ma ban hash khong phai la byte nguoi xuat ban hash - tai lai file hoac lay lai nguon. Mot ky tu hex khac biet la "du lieu vao khac nhau, lam lai toan bo", khong phai "gan dung, chi lam lai khoi cuoi".

Cac huong dan lien quan ve developer va MD5: MD5 vs SHA-256 - Khi Nao Hash (lua chon thuat toan), Tai Sao MD5 Khong The Giai Ma (vi sao MD5 khong nguoc duoc), MD5 Sang Text - Tai Sao Khong Chuyen Nguoc Duoc (doi tac van hanh), va Cac Lua Chon Thay The MD5 - bcrypt vs Argon2id vs SHA-256 (lua chon hien dai cho su dung doi khang).

Reviewed by the Free Tool Online editorial team · Tested in the current versions of Chrome, Firefox, Safari, and Edge before publishing. Your file is processed in your browser and never uploaded. Report a bug - we triage within 72 hours. · Last refreshed April 2026.

Why trust these tools

  • Ten-plus years of web tooling. The freetoolonline editorial team has shipped browser-based utilities since 2015. The goal has never changed: get you to a working output fast, without an install.
  • Truly in-browser - no upload. Every file-processing tool on this site runs in your browser through modern Web APIs (File, FileReader, Canvas, Web Audio, WebGL, Web Workers). Your photo, PDF, audio, or text never leaves your device.
  • No tracking during tool use. Analytics ends at the page view. The actual input you paste, drop, or capture is never sent to any server and never written to any log.
  • Open-source core components. The processing engines underneath (libheif, libde265, pdf-lib, terser, clean-css, ffmpeg.wasm, and others) are public and audit-able. We link to each one in its tool page's footer.
  • Free, with or without ads. All tools are fully functional without sign-up. The Disable Ads button in the header is always available if you need a distraction-free run.