Crate aescrypt_rs 

Fast, safe, streaming AES Crypt (v0–v3) encryption and decryption.

aescrypt-rs reads every published AES Crypt file format version (v0–v3) and writes the modern v3 format only. The public surface is intentionally small — most users only need encrypt(), decrypt(), and read_version() — but the lower-level KDF, header, session, and streaming primitives are exposed for custom flows.

Quick Start

Encrypt and decrypt data using AES Crypt format v3:

use aescrypt_rs::{encrypt, decrypt, PasswordString, constants::DEFAULT_PBKDF2_ITERATIONS};
use std::io::Cursor;

let password = PasswordString::new("correct horse battery staple".to_string());
let data = b"top secret";

// Encrypt
let mut ciphertext = Vec::new();
encrypt(Cursor::new(data), &mut ciphertext, &password, DEFAULT_PBKDF2_ITERATIONS)?;

// Decrypt
let mut plaintext = Vec::new();
decrypt(Cursor::new(&ciphertext), &mut plaintext, &password)?;

assert_eq!(data, &plaintext[..]);

Detect file format version without decrypting:

use aescrypt_rs::read_version;
use std::io::Cursor;

let header = b"AES\x03\x00";
let version = read_version(Cursor::new(header))?;
assert_eq!(version, 3);

Supported Formats

Operation	v0	v1	v2	v3
decrypt()	Y	Y	Y	Y
encrypt()	–	–	–	Y
read_version()	Y	Y	Y	Y

v3 is the only format produced on write. v0–v2 are read-only for compatibility with files generated by older AES Crypt tools.

Feature Flags

This crate defines no Cargo features. The following dependency feature flags are always enabled and cannot be disabled by downstream crates:

• aes/zeroize — automatic zeroization of AES round keys on drop.
• secure-gate/rand — CSPRNG-backed random IV/key/salt generation.
• secure-gate/ct-eq — constant-time HMAC and PKCS#7 padding comparisons.

Building with --no-default-features is a no-op; the security posture is fixed.

MSRV

Minimum Supported Rust Version is 1.70 (edition 2021). CI verifies the crate against cargo +1.70 test --all-features. See CHANGELOG.md for the dependency pin matrix that keeps the resolver honest on 1.70.

Security Model

• No unsafe in this crate — enforced by #![forbid(unsafe_code)]. Cryptographic backends and secure-gate may use unsafe internally; this crate does not.
• Key derivation: PBKDF2-HMAC-SHA512 for v3 (caller-controlled iterations, default DEFAULT_PBKDF2_ITERATIONS = 300 000), and the AES Crypt v0–v2 ACKDF (8192 SHA-256 iterations, UTF-16-LE password) for legacy reads.
• Bulk encryption: AES-256-CBC with PKCS#7 padding (v3) or legacy modulo padding (v0/v1/v2 read-only).
• Authentication: HMAC-SHA256 over the encrypted session block and ciphertext stream. Session and payload tags are compared with constant-time equality.
• Memory hygiene: keys, IVs, salts, passwords, and intermediate buffers are wrapped in secure-gate types (PasswordString, Aes256Key32, Iv16, Salt16, …) that zeroize on drop.
• Decrypt-then-verify: as defined by the AES Crypt format, the v3 payload HMAC is verified after the ciphertext stream is decrypted. decrypt() therefore may write partial unauthenticated plaintext to its output before returning an error — see decrypt() for the mandatory caller contract.
• PBKDF2 iteration bounds: enforced by the encryption path to [PBKDF2_MIN_ITER](constants::PBKDF2_MIN_ITER) ..= [PBKDF2_MAX_ITER](constants::PBKDF2_MAX_ITER). Lowering iterations weakens password resistance; do not go below DEFAULT_PBKDF2_ITERATIONS.

Errors

Every fallible operation in this crate returns Result<T, AescryptError>. The error variants are documented on AescryptError together with the public APIs that produce each variant.

Re-exports

pub use aliases::PasswordString;

pub use decryption::decrypt;

pub use decryption::decrypt;

pub use encryption::encrypt;

pub use encryption::encrypt;

pub use error::AescryptError;

pub use pbkdf2_builder::Pbkdf2Builder;

pub use kdf::ackdf::derive_ackdf_key;

pub use kdf::pbkdf2::derive_pbkdf2_key;

pub use header::read_version;

Modules

aliases

Secure-Gate Type Aliases

constants

Public configuration constants.

decryption

AES Crypt v0–v3 decryption surface.

encryption

AES Crypt v3 encryption surface.

error

Error types for AES Crypt operations.

header

AES Crypt file-header parsing.

kdf

Key Derivation Functions used by AES Crypt v0–v3.

pbkdf2_builder

Fluent builder for PBKDF2-HMAC-SHA512 key derivation.

utilities

Low-level utility functions used by the encryption and decryption pipelines.