Struct Parameters

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pub struct Parameters { /* private fields */ }

Expand description

The segment length is the only varying parameter in the current specification; AES-256-GCM, HKDF-Expand-SHA-384, and the 32-byte FLOE IV are fixed.

Use Parameters::with_segment_length to construct a Parameters instance with your desired segment length, or use one of the pre-made Parameters constants like Parameters::SEGMENT_4_KIB or Parameters::SEGMENT_1_MIB if convenient.

Implementations§

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impl Parameters

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pub const VALID_SEGMENT_LENGTHS: Range<u32>

Range of valid FLOE segment sizes in bytes. FLOE accepts any segment size in this range and is not restricted to powers of 2.

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pub const SEGMENT_64_B: Self

FLOE with 64-byte encrypted segments.

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pub const SEGMENT_4_KIB: Self

FLOE with 4 KiB encrypted segments.

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pub const SEGMENT_1_MIB: Self

FLOE with 1 MiB encrypted segments.

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pub const SEGMENT_4_MIB: Self

FLOE with 4 MiB encrypted segments.

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pub const SEGMENT_5_MIB: Self

FLOE with 5 MiB encrypted segments.

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pub const SEGMENT_8_MIB: Self

FLOE with 8 MiB encrypted segments.

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pub const SEGMENT_16_MIB: Self

FLOE with 16 MiB encrypted segments.

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pub fn with_segment_length(segment_len: u32) -> Result<Self>

Construct a Parameters instance with the provided segment length in bytes. segment_len can be any value in the range Parameters::VALID_SEGMENT_LENGTHS.

§Errors

Returns Error::InvalidSegmentLength when segment_len is outside the supported range.

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pub const fn ciphertext_segment_length(self) -> usize

Returns the exact length of every non-final ciphertext segment.

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pub const fn plaintext_segment_length(self) -> usize

Returns the plaintext length of every non-final segment and the maximum plaintext length of a final segment.

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pub fn plaintext_layout(self, plaintext_length: u64) -> Result<MessageLayout>

Calculates the complete FLOE layout for plaintext_length.

§Errors

Returns Error::SegmentLimit when the message would exceed the specification’s segment limit, or Error::LengthOverflow when the resulting ciphertext length cannot be represented as a u64.

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pub fn ciphertext_layout(self, ciphertext_length: u64) -> Result<MessageLayout>

Calculates the complete FLOE layout for ciphertext_length.

ciphertext_length includes the FLOE header. This validates only the lengths implied by the file size and assumes every preceding segment is a full non-final segment. Each prefix and authentication tag must still be validated while decrypting. For streaming input whose complete length is unavailable, use SegmentFraming::decode instead.