以下详细说明暂以英文提供。
What a SHA-256 hash is good for
SHA-256 squeezes any input — a password, a file, a whole novel — into a fixed 256-bit fingerprint. Change one character anywhere and roughly half the output bits flip, which makes the digest a rigorous equality check: publish the hash of a download so readers can verify it, compare a freshly typed configuration against a known-good digest, or deduplicate content without storing it. Identical input always yields the identical digest, and no practical method is known for finding two inputs that share one.
Hashing is not encryption
The two get confused constantly, and the difference matters. Encryption is reversible by design: with the key you get the original back. A hash is one-way — the digest is not a scrambled copy of your text but a short summary from which the text cannot be recovered. That is exactly why passwords should be hashed, not encrypted, on a server; and it is also why a hashed password cannot be "unhashed" by this or any tool. For passwords in the real world, use a slow, memory-hard scheme such as Argon2 or bcrypt rather than raw SHA-256.
中国本地参考
日常计算时值得知道的中国本地规则：
- 计量的单位习惯: 住房面积用平方米，土地常用亩（1 亩 ≈ 666.7 平方米）；里程用公里，油耗用 L/100km。
- 日期与数字格式: 日期写作 2026年10月13日（年-月-日）；大数习惯用万、亿（1 万 = 10,000，1 亿 = 100,000,000）。
- 法定节假日: 全年法定节假日 11 天，春节与国庆为长假；调休安排每年由国务院办公厅发布。
- 速度与限速: 高速公路最高限速 120 km/h，城市快速路多为 80 km/h，均以公里每小时计。
- 鞋服尺码: 鞋码用中国码（毫米制），服装常用 155/80A 这类身高围度组合，与欧美码不同。
数据核对：2026 年 10 月
常见问题
Does my text get sent to a server?
No. The SHA-256 implementation runs in JavaScript on this page, so hashing happens on your device. The text you type never leaves the browser, which makes the tool safe for secrets you only need to fingerprint.
Why only SHA-256?
SHA-256 is the modern default: fast, widely supported, and unbroken. Older functions such as MD5 and SHA-1 are kept around only for legacy compatibility because collisions have been demonstrated against both, so this tool skips them.
Can two different texts have the same hash?
Mathematically yes — 256 bits cannot name every possible input uniquely — but no collision has ever been found for SHA-256, and finding one by brute force would take more energy than burning all the world’s fossil fuel. For any practical purpose, equal digests mean equal inputs.