mirror of
https://github.com/BLAKE3-team/BLAKE3
synced 2024-05-19 04:56:08 +02:00
4d6dfc4eed
Changes since 1.0.0: - The NEON implementation is now enabled by default on AArch64 targets. Previously it was disabled without the "neon" Cargo feature in Rust or the "BLAKE3_USE_NEON=1" preprocessor flag in C. This is still the case on ARM targets other than AArch64, because of the lack of dynamic CPU feature detection on ARM. Contributed by @rsdy. - The previous change leads to some build incompatibilities, particularly in C. If you build the C implementation for AArch64 targets, you now need to include blake3_neon.c, or else you'll get a linker error like "undefined reference to `blake3_hash_many_neon'". If you don't want the NEON implementation, you need to explicitly set "BLAKE3_USE_NEON=0". On the Rust side, AArch64 targets now require the C toolchain by default. build.rs includes workarounds for missing or very old C compilers for x86, but it doesn't currently include such workarounds for AArch64. If we hear about build breaks related to this, we can add more workarounds as appropriate. - C-specific Git tags ("c-0.3.7" etc.) have been removed, and all the projects in this repo (Rust "blake3", Rust "b3sum", and the C implementation) will continue to be versioned in lockstep for the foreseeable future.
87 lines
3.0 KiB
Markdown
87 lines
3.0 KiB
Markdown
# b3sum
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A command line utility for calculating
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[BLAKE3](https://github.com/BLAKE3-team/BLAKE3) hashes, similar to
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Coreutils tools like `b2sum` or `md5sum`.
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```
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b3sum 1.1.0
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USAGE:
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b3sum [FLAGS] [OPTIONS] [FILE]...
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FLAGS:
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-c, --check Reads BLAKE3 sums from the [file]s and checks them
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-h, --help Prints help information
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--keyed Uses the keyed mode. The secret key is read from standard
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input, and it must be exactly 32 raw bytes.
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--no-mmap Disables memory mapping. Currently this also disables
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multithreading.
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--no-names Omits filenames in the output
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--quiet Skips printing OK for each successfully verified file.
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Must be used with --check.
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--raw Writes raw output bytes to stdout, rather than hex.
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--no-names is implied. In this case, only a single
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input is allowed.
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-V, --version Prints version information
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OPTIONS:
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--derive-key <CONTEXT> Uses the key derivation mode, with the given
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context string. Cannot be used with --keyed.
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-l, --length <LEN> The number of output bytes, prior to hex
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encoding (default 32)
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--num-threads <NUM> The maximum number of threads to use. By
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default, this is the number of logical cores.
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If this flag is omitted, or if its value is 0,
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RAYON_NUM_THREADS is also respected.
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ARGS:
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<FILE>... Files to hash, or checkfiles to check. When no file is given,
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or when - is given, read standard input.
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```
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See also [this document about how the `--check` flag
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works](https://github.com/BLAKE3-team/BLAKE3/blob/master/b3sum/what_does_check_do.md).
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# Example
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Hash the file `foo.txt`:
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```bash
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b3sum foo.txt
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```
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Time hashing a gigabyte of data, to see how fast it is:
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```bash
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# Create a 1 GB file.
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head -c 1000000000 /dev/zero > /tmp/bigfile
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# Hash it with SHA-256.
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time openssl sha256 /tmp/bigfile
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# Hash it with BLAKE3.
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time b3sum /tmp/bigfile
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```
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# Installation
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Prebuilt binaries are available for Linux, Windows, and macOS (requiring
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the [unidentified developer
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workaround](https://support.apple.com/guide/mac-help/open-a-mac-app-from-an-unidentified-developer-mh40616/mac))
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on the [releases page](https://github.com/BLAKE3-team/BLAKE3/releases).
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If you've [installed Rust and
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Cargo](https://doc.rust-lang.org/cargo/getting-started/installation.html),
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you can also build `b3sum` yourself with:
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```
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cargo install b3sum
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```
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On Linux for example, Cargo will put the compiled binary in
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`~/.cargo/bin`. You might want to add that directory to your `$PATH`, or
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`rustup` might have done it for you when you installed Cargo.
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If you want to install directly from this directory, you can run `cargo
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install --path .`. Or you can just build with `cargo build --release`,
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which puts the binary at `./target/release/b3sum`.
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