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// MIT License // Copyright (c) 2018-2020 The orion Developers // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. //! Key derivation. //! //! # Use case: //! `orion::kdf` can be used to derive higher-entropy keys from low-entropy //! keys. Also known as key stretching. //! //! An example of this could be deriving a key from a user-submitted password //! and using this derived key in disk encryption. //! //! # About: //! - Uses Argon2i. //! //! # Note: //! This implementation only supports a single thread/lane. //! //! # Parameters: //! - `password`: The low-entropy input key to be used in key derivation. //! - `expected`: The expected derived key. //! - `salt`: The salt used for the key derivation. //! - `iterations`: Iterations cost parameter for Argon2i. //! - `memory`: Memory (in kibibytes (KiB)) cost parameter for Argon2i. //! - `length`: The desired length of the derived key. //! //! # Errors: //! An error will be returned if: //! - `iterations` is less than 3. //! - `length` is less than 4. //! - `memory` is less than 8. //! - The length of the `password` or `expected` is greater than `u32::max_value()`. //! - The length of the `salt` is greater than `u32::max_value()` or less than `8`. //! - The `expected` does not match the derived key. //! //! # Security: //! - Choosing the correct cost parameters is important for security. Please refer to //! [libsodium's docs](https://download.libsodium.org/doc/password_hashing/default_phf#guidelines-for-choosing-the-parameters) //! for a description of how to do this. //! - The salt should always be generated using a CSPRNG. [`Salt::default()`] //! can be used for this, it will generate a [`Salt`] of 16 bytes. //! - The recommended minimum size for a salt is 16 bytes. //! - The recommended minimum size for a derived key is 16 bytes. //! //! # Example: //! ```rust //! use orion::kdf; //! //! let user_password = kdf::Password::from_slice(b"User password")?; //! let salt = kdf::Salt::default(); //! //! let derived_key = kdf::derive_key(&user_password, &salt, 3, 1<<16, 32)?; //! //! assert!(kdf::derive_key_verify(&derived_key, &user_password, &salt, 3, 1<<16).is_ok()); //! # Ok::<(), orion::errors::UnknownCryptoError>(()) //! ``` //! [`Salt`]: struct.Salt.html //! [`Salt::default()`]: struct.Salt.html pub use super::hltypes::{Password, Salt, SecretKey}; use crate::{errors::UnknownCryptoError, hazardous::kdf::argon2i, pwhash::MIN_ITERATIONS}; #[must_use = "SECURITY WARNING: Ignoring a Result can have real security implications."] /// Derive a key using Argon2i. pub fn derive_key( password: &Password, salt: &Salt, iterations: u32, memory: u32, length: u32, ) -> Result<SecretKey, UnknownCryptoError> { if iterations < MIN_ITERATIONS { return Err(UnknownCryptoError); } let mut dk = SecretKey::from_slice(&vec![0u8; length as usize])?; argon2i::derive_key( password.unprotected_as_bytes(), salt.as_ref(), iterations, memory, None, None, &mut dk.value, )?; Ok(dk) } #[must_use = "SECURITY WARNING: Ignoring a Result can have real security implications."] /// Derive and verify a key using Argon2i. pub fn derive_key_verify( expected: &SecretKey, password: &Password, salt: &Salt, iterations: u32, memory: u32, ) -> Result<(), UnknownCryptoError> { if iterations < MIN_ITERATIONS { return Err(UnknownCryptoError); } let mut dk = SecretKey::from_slice(&vec![0u8; expected.len()])?; argon2i::verify( expected.unprotected_as_bytes(), password.unprotected_as_bytes(), salt.as_ref(), iterations, memory, None, None, &mut dk.value, ) } // Testing public functions in the module. #[cfg(test)] mod public { use super::*; mod test_derive_key_and_verify { use super::*; #[test] fn test_derive_key_and_verify() { let password = Password::from_slice(&[0u8; 64]).unwrap(); let salt = Salt::from_slice(&[0u8; 16]).unwrap(); let dk = derive_key(&password, &salt, 3, 1024, 32).unwrap(); assert!(derive_key_verify(&dk, &password, &salt, 3, 1024).is_ok()); } #[test] fn test_derive_key_and_verify_err_diff_iter() { let password = Password::from_slice(&[0u8; 64]).unwrap(); let salt = Salt::from_slice(&[0u8; 64]).unwrap(); let dk = derive_key(&password, &salt, 3, 1024, 32).unwrap(); assert!(derive_key_verify(&dk, &password, &salt, 4, 1024).is_err()); } #[test] fn test_derive_key_and_verify_err_diff_mem() { let password = Password::from_slice(&[0u8; 64]).unwrap(); let salt = Salt::from_slice(&[0u8; 64]).unwrap(); let dk = derive_key(&password, &salt, 3, 1024, 32).unwrap(); assert!(derive_key_verify(&dk, &password, &salt, 3, 512).is_err()); } #[test] fn test_derive_key_bad_length() { let password = Password::from_slice(&[0u8; 64]).unwrap(); let salt = Salt::from_slice(&[0u8; 64]).unwrap(); assert!(derive_key(&password, &salt, 3, 1024, 3).is_err()); assert!(derive_key(&password, &salt, 3, 1024, 4).is_ok()); assert!(derive_key(&password, &salt, 3, 1024, 5).is_ok()); } #[test] fn test_derive_key_bad_iter() { let password = Password::from_slice(&[0u8; 64]).unwrap(); let salt = Salt::from_slice(&[0u8; 16]).unwrap(); let dk = derive_key(&password, &salt, 3, 1024, 32).unwrap(); assert!(derive_key(&password, &salt, 2, 1024, 32).is_err()); assert!(derive_key(&password, &salt, 3, 1024, 32).is_ok()); assert!(derive_key(&password, &salt, 4, 1024, 32).is_ok()); assert!(derive_key_verify(&dk, &password, &salt, 2, 1024).is_err()); assert!(derive_key_verify(&dk, &password, &salt, 3, 1024).is_ok()); } #[test] fn test_derive_key_bad_mem() { let password = Password::from_slice(&[0u8; 64]).unwrap(); let salt = Salt::from_slice(&[0u8; 16]).unwrap(); let dk = derive_key(&password, &salt, 3, 8, 32).unwrap(); assert!(derive_key(&password, &salt, 3, 7, 32).is_err()); assert!(derive_key(&password, &salt, 3, 8, 32).is_ok()); assert!(derive_key(&password, &salt, 3, 9, 32).is_ok()); assert!(derive_key_verify(&dk, &password, &salt, 3, 7).is_err()); assert!(derive_key_verify(&dk, &password, &salt, 3, 8).is_ok()); } } }