Crate udigest

Unambiguously digest structured data

udigest provides utilities for unambiguous hashing the structured data. Structured data can be anything that implements Digestable trait:

• str, String, CStr, CString
• Integers: i8, i16, i32, i64, i128, u8, u16, u32, u64, u128, char, isize, usize
• Containers: Box, Arc, Rc, Cow, Option, Result
• Collections: arrays, slices, Vec, LinkedList, VecDeque, BTreeSet, BTreeMap

The trait is intentionally not implemented for certain types:

• HashMap, HashSet as they can not be traversed in deterministic order

The Digestable trait can be implemented for the struct using a macro:

#[derive(udigest::Digestable)]
struct Person {
    name: String,
    job_title: String,   
}
let alice = Person {
    name: "Alice".into(),
    job_title: "cryptographer".into(),
};

let hash = udigest::hash::<sha2::Sha256>(&alice);

The crate intentionally does not try to follow any existing standards for unambiguous encoding. The format for encoding was designed specifically for udigest to provide a better usage experience in Rust. The details of encoding format can be found in encoding module.

Features

• digest enables support of hash functions that implement digest traits
  If feature is not enabled, the crate is still usable via Digestable trait that generically implements unambiguous encoding
• inline-struct is required to use inline_struct! macro
• std implements Digestable trait for types in standard library
• alloc implements Digestable trait for type in alloc crate
• derive enables Digestable proc macro

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Re-exports

• pub use encoding::Buffer;
• pub use as_::DigestAs;

Modules

• as_
  Provides utilities for custom digesting rules
• encoding
  Unambiguous encoding
• inline_structinline-struct
  Digestable inline structs

Macros

• inline_structinline-struct
  Creates digestable inline struct

Structs

• Bytes
  Wrapper for a bytestring

Traits

• Digestable
  A value that can be unambiguously digested

Functions

• hashdigest
  Digests a structured value using fixed-output hash function (like sha2-256)
• hash_iterdigest
  Digests a list of structured data using fixed-output hash function (like sha2-256)
• hash_vofdigest
  Digests a structured value using variable-output hash function (like blake2b)
• hash_vof_iterdigest
  Digests a list of structured data using variable-output hash function (like blake2b)
• hash_xofdigest
  Digests a structured value using extendable-output hash function (like shake-256)
• hash_xof_iterdigest
  Digests a list of structured data using extendable-output hash function (like shake-256)

Derive Macros

• Digestablederive
  Derives a Digestable trait