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Hash tools

MD5, SHA-1, SHA-256, SHA-384, SHA-512, or CRC-32 from text, encoded bytes, or a local file. Choose input encoding, hex or Base64 output, and optional HMAC.

7 tools

What a hash function is

A hash is deterministic and one-way for practical purposes. The same bytes always produce the same digest. You cannot recover the input from the digest alone. A hash is not encryption. Anyone can hash the same input and compare.

Which hash to use

Use SHA-256 or SHA-512 for new integrity checks. Use MD5 or SHA-1 only to match a published legacy checksum. CRC-32 is ISO-HDLC, not a cryptographic hash. File checksum hashes a local file of 32 MB or less.

Input encoding and HMAC

Set input encoding to match the bytes you hash. UTF-8 is correct for ordinary text. Use hex or Base64 when the paste is already encoded bytes. HMAC adds a key. The digest then depends on both the message and the key.