César Sagaert
51 lines
1.8 KiB
TOML
51 lines
1.8 KiB
TOML
name = "bigints"
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description = "Experimental SPARK Constant Time Big Integer library"
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version = "0.2.0"
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authors = ["César SAGAERT"]
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maintainers = ["César SAGAERT <sagaert@adacore.com>"]
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maintainers-logins = ["AldanTanneo"]
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licenses = "MIT"
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website = "https://github.com/AldanTanneo/bigints"
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tags = ["bigint", "cryptography", "constant-time", "spark", "ada2022"]
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long-description = """# SPARK Constant Time Big Integer library
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Implementation of a constant time big integer library, inspired by [crypto-bigint](https://github.com/RustCrypto/crypto-bigint).
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All functions are implemented in constant time, except those with an explicit `_Vartime` suffix. Overloaded operators are also constant time.
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> \u26A0\uFE0F The constant time choice primitives like `Ct_Eq`, `Ct_Gt`, `Cond_Select` and `CSwap` rely on best-effort optimisation barriers.
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## Usage
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The implementations are generic over the size of the integer:
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```ada
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package U256 is new Bigints.Uint (256);
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package U1024 is new Bigints.Uint (1024);
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```
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There is also a generic package to deal with modular integers (over a prime field):
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```ada
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P : U256.Uint := ... -- a big prime, like 2**255 - 19
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package GF_P is new Bigints.Modular (U256, P);
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```
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It is up to the user of the library to ensure the chosen modulus is effectively prime. Otherwise, operations like field inversion become invalid (as it relies on Fermat's little theorem).
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## Formal proof
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The preinstantations in the library (packages `U256s` and `F25519`), as well as the constant time primitives and basic limb primitives, are formally checked using GNATprove.
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"""
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[build-switches]
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"*".ada_version = "Ada2022"
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development.optimization = ["-O3"]
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release.runtime_checks = "none"
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[origin]
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commit = "414589c10e5dec87aebf9cfe8fda675a047d45b1"
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url = "git+https://github.com/AldanTanneo/bigints.git"
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