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94 lines
2.7 KiB
Python
94 lines
2.7 KiB
Python
"""
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Define input parameters for test vector generation.
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:ivar CONVERGENCE_SECRETS: Convergence secrets.
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:ivar SEGMENT_SIZE: The single segment size that the Python implementation
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currently supports without a lot of refactoring.
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:ivar OBJECT_DESCRIPTIONS: Small objects with instructions which can be
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expanded into a possibly large byte string. These are intended to be used
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as plaintext inputs.
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:ivar ZFEC_PARAMS: Input parameters to ZFEC.
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:ivar FORMATS: Encoding/encryption formats.
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"""
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from __future__ import annotations
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from hashlib import sha256
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from .model import MAX_SHARES
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from .vectors import Sample, SeedParam
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from ..util import CHK, SSK
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def digest(bs: bytes) -> bytes:
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"""
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Digest bytes to bytes.
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"""
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return sha256(bs).digest()
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def hexdigest(bs: bytes) -> str:
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"""
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Digest bytes to text.
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"""
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return sha256(bs).hexdigest()
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# Just a couple convergence secrets. The only thing we do with this value is
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# feed it into a tagged hash. It certainly makes a difference to the output
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# but the hash should destroy any structure in the input so it doesn't seem
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# like there's a reason to test a lot of different values.
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CONVERGENCE_SECRETS: list[bytes] = [
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b"aaaaaaaaaaaaaaaa",
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digest(b"Hello world")[:16],
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]
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SEGMENT_SIZE: int = 128 * 1024
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# Exercise at least a handful of different sizes, trying to cover:
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#
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# 1. Some cases smaller than one "segment" (128k).
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# This covers shrinking of some parameters to match data size.
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# This includes one case of the smallest possible CHK.
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#
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# 2. Some cases right on the edges of integer segment multiples.
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# Because boundaries are tricky.
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#
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# 4. Some cases that involve quite a few segments.
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# This exercises merkle tree construction more thoroughly.
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#
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# See ``stretch`` for construction of the actual test data.
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OBJECT_DESCRIPTIONS: list[Sample] = [
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# The smallest possible. 55 bytes and smaller are LIT.
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Sample(b"a", 56),
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Sample(b"a", 1024),
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Sample(b"c", 4096),
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Sample(digest(b"foo"), SEGMENT_SIZE - 1),
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Sample(digest(b"bar"), SEGMENT_SIZE + 1),
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Sample(digest(b"baz"), SEGMENT_SIZE * 16 - 1),
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Sample(digest(b"quux"), SEGMENT_SIZE * 16 + 1),
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Sample(digest(b"bazquux"), SEGMENT_SIZE * 32),
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Sample(digest(b"foobar"), SEGMENT_SIZE * 64 - 1),
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Sample(digest(b"barbaz"), SEGMENT_SIZE * 64 + 1),
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]
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ZFEC_PARAMS: list[SeedParam] = [
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SeedParam(1, 1),
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SeedParam(1, 3),
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SeedParam(2, 3),
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SeedParam(3, 10),
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SeedParam(71, 255),
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SeedParam(101, MAX_SHARES),
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]
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FORMATS: list[CHK | SSK] = [
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CHK(),
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# These start out unaware of a key but various keys will be supplied
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# during generation.
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SSK(name="sdmf", key=None),
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SSK(name="mdmf", key=None),
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]
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