CRC32チェックサムジェネレータ
任意のテキストまたはアップロードされたファイルのCRC-32（IEEE 802.3）チェックサムを計算します—zip、gzip、PNGで使用されるのと同じアルゴリズム—8桁の大文字の16進値として。
入力
出力
このツールを使う他の方法
REST API
curl -X POST https://api.iotools.cloud/v1/tool/crc32-checksum-generator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"inputText": "123456789"
}'ご自身のアカウントのキーに差し替えてください。ツールのフィールドがそのままリクエストボディになります——ラッパーはありません。
AIエージェントに依頼する
Use the IOTools `crc32-checksum-generator` tool (CRC32 Checksum Generator) on this input:
YOUR_INPUT_HEREIOTools MCPサーバーに接続された任意のエージェントにこれを貼り付け、入力内容を追加してください。
埋め込みウィジェット
<iframe
src="https://iotools.cloud/embed/crc32-checksum-generator/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="CRC32チェックサムジェネレータ — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>ご自身のページに貼り付けるだけ——無料、キー不要、リンクを掲載するだけです。
| API/MCP 1回あたりの費用 | 5クレジットから |
|---|---|
| クレジットが足りませんか? | 料金を見る |
次の方法でも利用可能
ガイド
The CRC32 Checksum Generator computes the CRC-32 checksum of any text or file. Type or paste text, or upload a file, and the tool returns an 8-digit uppercase hexadecimal value — the same checksum format used by zip archives, gzip compression, and PNG images.
CRC-32 (Cyclic Redundancy Check, 32-bit) is not a cryptographic hash — it's designed to catch accidental data corruption (a flipped bit during a transfer or a truncated download), not to resist deliberate tampering. It's fast, has a short fixed-length output, and is built into countless file formats and network protocols, which is why it remains a useful general-purpose integrity check.
How to use it
- Enter your text in the input box, or upload a file using the uploader above it.
- The CRC-32 checksum appears instantly as an 8-digit uppercase hex value (e.g.
CBF43926). - Use the copy or download button to save the result.
Uploading a file fills the same text box with its contents, so you only ever need one input — paste text directly, or drop a file to check it instead.
Which polynomial does this use?
This tool computes the standard CRC-32 defined by IEEE 802.3, using the (reversed) polynomial 0xEDB88320. It's the variant used by zip, gzip, PNG, Ethernet frame checking, and most "CRC32" checksum utilities you'll find elsewhere — if another tool's CRC-32 doesn't match this one, double-check it isn't computing CRC-32C (Castagnoli, used by iSCSI and ext4) or including a different byte encoding of your text.
Why doesn't my file's CRC32 match this tool's output for the same text?
Text encoding matters. This tool encodes text as UTF-8 before hashing, so pasting the same characters that were saved in a file with a different encoding (UTF-16, Latin-1) will produce a different checksum, even though the characters look identical on screen. Binary files aren't affected by this, since a CRC-32 of file bytes doesn't involve text encoding at all.
Is CRC-32 secure enough for verifying downloads or passwords?
No. CRC-32 is trivial to forge — an attacker can construct a different file with the same checksum in seconds. It's suitable for detecting accidental corruption, not for verifying authenticity or storing passwords. For security-sensitive integrity checks, use a cryptographic hash like SHA-256 (see the Hash Generator).
What's the CRC-32 of an empty input?
00000000. An empty message has nothing to checksum, so the algorithm returns its initial value unchanged.
Privacy
Everything runs entirely in your browser. Your text or file is never uploaded to a server — the checksum is computed locally and only the result you choose to copy or download ever leaves your device.