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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /Documentation/crypto/sha3.rst | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'Documentation/crypto/sha3.rst')
| -rw-r--r-- | Documentation/crypto/sha3.rst | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/Documentation/crypto/sha3.rst b/Documentation/crypto/sha3.rst new file mode 100644 index 000000000..250669c98 --- /dev/null +++ b/Documentation/crypto/sha3.rst @@ -0,0 +1,132 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +.. _sha3: + +========================== +SHA-3 Algorithm Collection +========================== + +.. contents:: + +Overview +======== + +The SHA-3 family of algorithms, as specified in NIST FIPS-202 [1]_, contains six +algorithms based on the Keccak sponge function. The differences between them +are: the "rate" (how much of the state buffer gets updated with new data between +invocations of the Keccak function and analogous to the "block size"), what +domain separation suffix gets appended to the input data, and how much output +data is extracted at the end. The Keccak sponge function is designed such that +arbitrary amounts of output can be obtained for certain algorithms. + +Four digest algorithms are provided: + + - SHA3-224 + - SHA3-256 + - SHA3-384 + - SHA3-512 + +Additionally, two Extendable-Output Functions (XOFs) are provided: + + - SHAKE128 + - SHAKE256 + +The SHA-3 library API supports all six of these algorithms. The four digest +algorithms are also supported by the crypto_shash and crypto_ahash APIs. + +This document describes the SHA-3 library API. + + +Digests +======= + +The following functions compute SHA-3 digests:: + + void sha3_224(const u8 *in, size_t in_len, u8 out[SHA3_224_DIGEST_SIZE]); + void sha3_256(const u8 *in, size_t in_len, u8 out[SHA3_256_DIGEST_SIZE]); + void sha3_384(const u8 *in, size_t in_len, u8 out[SHA3_384_DIGEST_SIZE]); + void sha3_512(const u8 *in, size_t in_len, u8 out[SHA3_512_DIGEST_SIZE]); + +For users that need to pass in data incrementally, an incremental API is also +provided. The incremental API uses the following struct:: + + struct sha3_ctx { ... }; + +Initialization is done with one of:: + + void sha3_224_init(struct sha3_ctx *ctx); + void sha3_256_init(struct sha3_ctx *ctx); + void sha3_384_init(struct sha3_ctx *ctx); + void sha3_512_init(struct sha3_ctx *ctx); + +Input data is then added with any number of calls to:: + + void sha3_update(struct sha3_ctx *ctx, const u8 *in, size_t in_len); + +Finally, the digest is generated using:: + + void sha3_final(struct sha3_ctx *ctx, u8 *out); + +which also zeroizes the context. The length of the digest is determined by the +initialization function that was called. + + +Extendable-Output Functions +=========================== + +The following functions compute the SHA-3 extendable-output functions (XOFs):: + + void shake128(const u8 *in, size_t in_len, u8 *out, size_t out_len); + void shake256(const u8 *in, size_t in_len, u8 *out, size_t out_len); + +For users that need to provide the input data incrementally and/or receive the +output data incrementally, an incremental API is also provided. The incremental +API uses the following struct:: + + struct shake_ctx { ... }; + +Initialization is done with one of:: + + void shake128_init(struct shake_ctx *ctx); + void shake256_init(struct shake_ctx *ctx); + +Input data is then added with any number of calls to:: + + void shake_update(struct shake_ctx *ctx, const u8 *in, size_t in_len); + +Finally, the output data is extracted with any number of calls to:: + + void shake_squeeze(struct shake_ctx *ctx, u8 *out, size_t out_len); + +and telling it how much data should be extracted. Note that performing multiple +squeezes, with the output laid consecutively in a buffer, gets exactly the same +output as doing a single squeeze for the combined amount over the same buffer. + +More input data cannot be added after squeezing has started. + +Once all the desired output has been extracted, zeroize the context:: + + void shake_zeroize_ctx(struct shake_ctx *ctx); + + +Testing +======= + +To test the SHA-3 code, use sha3_kunit (CONFIG_CRYPTO_LIB_SHA3_KUNIT_TEST). + +Since the SHA-3 algorithms are FIPS-approved, when the kernel is booted in FIPS +mode the SHA-3 library also performs a simple self-test. This is purely to meet +a FIPS requirement. Normal testing done by kernel developers and integrators +should use the much more comprehensive KUnit test suite instead. + + +References +========== + +.. [1] https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf + + +API Function Reference +====================== + +.. kernel-doc:: include/crypto/sha3.h |
