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FileHash

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FileHash["file"]
gives an integer hash code for the contents of the specified file.
FileHash["file", "type"]
gives an integer hash of the specified type.
  • Values generated by FileHash are based on the raw bytes in a file.
  • Possible hash code types include:
"Adler32"Adler 32-bit cyclic redundancy check
"CRC32"32-bit cyclic redundancy check
"MD2"128-bit MD2 code
"MD5"128-bit MD5 code
"SHA"160-bit SHA-1 code
"SHA256"256-bit SHA code
"SHA384"384-bit SHA code
"SHA512"512-bit SHA code
  • FileHash by default uses 128-bit MD5 code.
  • FileHash["file", "type", n] gives the hash code for the first n bytes of the file.
  • FileHash["file", "type", -n] gives the hash code for the last n bytes.
  • FileHash["file", "type", {m, n}] gives the hash code for bytes m through n.
  • FileHash["file", "type", 0] gives the hash code for 0 bytes.
  • FileHash works not only on files, but also on streams.
  • FileHash[obj, ...] effectively extracts data at the specified range of byte positions in the stream obj, ignoring any previous stream position.
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