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https://github.com/saymrwulf/dalek-ed25519-verified.git
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37 lines
1.7 KiB
Text
37 lines
1.7 KiB
Text
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-- Hand-written external function models for the Scalar52 arithmetic extraction.
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-- The two subtle items reuse the field extraction's proven models verbatim.
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import Aeneas
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import CurveScalar.Types
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open Aeneas Aeneas.Std Result ControlFlow Error
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set_option linter.dupNamespace false
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set_option linter.hashCommand false
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set_option linter.unusedVariables false
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set_option maxHeartbeats 1000000
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set_option maxRecDepth 2048
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open curve25519_dalek
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/-- [subtle::{impl core::convert::From<u8> for subtle::Choice}::from]:
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Source: '/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/subtle-2.6.1/src/lib.rs', lines 238:4-238:32
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Name pattern: [subtle::{core::convert::From<subtle::Choice, u8>}::from]
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MODEL (faithful): Rust body is `Choice(black_box(input))`; the volatile
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read in `black_box` is semantically the identity. -/
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@[rust_fun "subtle::{core::convert::From<subtle::Choice, u8>}::from"]
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def subtle.Choice.Insts.CoreConvertFromU8.from
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(b : Std.U8) : Result subtle.Choice :=
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ok b
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/-- [subtle::{impl subtle::ConditionallySelectable for u64}::conditional_select]:
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Source: '/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/subtle-2.6.1/src/lib.rs', lines 513:12-513:77
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Name pattern: [subtle::{subtle::ConditionallySelectable<u64>}::conditional_select]
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MODEL: `a` if choice = 0, else `b`. The Rust mask trick
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`a ^ (-(choice as i64) as u64 & (a ^ b))` agrees with this on the Choice
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invariant {0,1} (mask = 0 or all-ones). -/
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@[rust_fun
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"subtle::{subtle::ConditionallySelectable<u64>}::conditional_select"]
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def U64.Insts.SubtleConditionallySelectable.conditional_select
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(a b : Std.U64) (choice : subtle.Choice) : Result Std.U64 :=
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ok (if choice.val = 0 then a else b)
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