Struct Oaep 

pub struct Oaep<D, MGD = D> {
    pub digest: D,
    pub mgf_digest: MGD,
    pub label: Option<Box<[u8]>>,
}

Encryption and Decryption using OAEP padding.

• digest is used to hash the label. The maximum possible plaintext length is m = k - 2 * h_len - 2, where k is the size of the RSA modulus.
• mgf_digest specifies the hash function that is used in the MGF1.
• label is optional data that can be associated with the message.

The two hash functions can, but don’t need to be the same.

A prominent example is the AndroidKeyStore. It uses SHA-1 for mgf_digest and a user-chosen SHA flavour for digest.

Fields

digest: D

Digest type to use.

mgf_digest: MGD

Digest to use for Mask Generation Function (MGF).

label: Option<Box<[u8]>>

Optional label.

Implementations

impl<D> Oaep<D>

where D: Digest + FixedOutputReset,

pub fn new() -> Oaep<D>

Create a new OAEP PaddingScheme, using T as the hash function for both the default (empty) label and for MGF1.

Example

use sha1::Sha1;
use sha2::Sha256;
use rsa::{RsaPublicKey, Oaep};
use base64ct::{Base64, Encoding};
use crypto_bigint::BoxedUint;

let n_bytes = Base64::decode_vec("seAOhmYFAjH6NOaB54dboqw86uPXV/oK9ayJGV4mVClbvsDBJmF3bVkOaVMp9ogcFJTFFSy5g2HsTZIfHyuQVUJADb+BeRnkYrYhRvNJOKj2pcDbkxYe9XGMx8pIvxkDFnIpusb3gUsuzMUAU5qIstjwQKzuD51c6uJi0HAtQkr6Wmlt34SX7xkD/MfRuTu9uqmHmkiiJaCDHB2reYTPguetSWfuvp1qBJDNgSsp7BjwYANWldyrmZ8cLXEXYMUG5vtsWMxUzl8ertEr6kbnGM0OJghNuEtittW/dfTPvk683R1jj0hNaMzvHK8xYldUlLuwmWCYIIvpHBaA/w+FwQ==").unwrap();
let e_bytes = Base64::decode_vec("AQAB").unwrap();
let n = BoxedUint::from_be_slice(&n_bytes, 2048).unwrap();
let e = BoxedUint::from_be_slice(&e_bytes, 32).unwrap();

let mut rng = rand::rng();
let key = RsaPublicKey::new(n, e).unwrap();
let padding = Oaep::<Sha256>::new();
let encrypted_data = key.encrypt(&mut rng, padding, b"secret").unwrap();

pub fn new_with_label<S>(label: S) -> Oaep<D>

where S: Into<Box<[u8]>>,

Create a new OAEP PaddingScheme with an associated label, using T as the hash function for both the label and for MGF1.

impl<D, MGD> Oaep<D, MGD>

where D: Digest + FixedOutputReset, MGD: Digest + FixedOutputReset,

pub fn new_with_mgf_hash() -> Oaep<D, MGD>

Create a new OAEP PaddingScheme, using T as the hash function for the default (empty) label, and U as the hash function for MGF1. If a label is needed use PaddingScheme::new_oaep_with_label or PaddingScheme::new_oaep_with_mgf_hash_with_label.

Example

use sha1::Sha1;
use sha2::Sha256;
use rsa::{RsaPublicKey, Oaep};
use base64ct::{Base64, Encoding};
use crypto_bigint::BoxedUint;

let n_bytes = Base64::decode_vec("seAOhmYFAjH6NOaB54dboqw86uPXV/oK9ayJGV4mVClbvsDBJmF3bVkOaVMp9ogcFJTFFSy5g2HsTZIfHyuQVUJADb+BeRnkYrYhRvNJOKj2pcDbkxYe9XGMx8pIvxkDFnIpusb3gUsuzMUAU5qIstjwQKzuD51c6uJi0HAtQkr6Wmlt34SX7xkD/MfRuTu9uqmHmkiiJaCDHB2reYTPguetSWfuvp1qBJDNgSsp7BjwYANWldyrmZ8cLXEXYMUG5vtsWMxUzl8ertEr6kbnGM0OJghNuEtittW/dfTPvk683R1jj0hNaMzvHK8xYldUlLuwmWCYIIvpHBaA/w+FwQ==").unwrap();
let e_bytes = Base64::decode_vec("AQAB").unwrap();
let n = BoxedUint::from_be_slice(&n_bytes, 2048).unwrap();
let e = BoxedUint::from_be_slice(&e_bytes, 32).unwrap();

let mut rng = rand::rng();
let key = RsaPublicKey::new(n, e).unwrap();
let padding = Oaep::<Sha256, Sha1>::new_with_mgf_hash();
let encrypted_data = key.encrypt(&mut rng, padding, b"secret").unwrap();

pub fn new_with_mgf_hash_and_label<S>(label: S) -> Oaep<D, MGD>

where S: Into<Box<[u8]>>,

Create a new OAEP PaddingScheme with an associated label, using T as the hash function for the label, and U as the hash function for MGF1.

Trait Implementations

impl<D, MGD> Debug for Oaep<D, MGD>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<D> Default for Oaep<D>

where D: Digest + FixedOutputReset,

fn default() -> Oaep<D>

Returns the “default value” for a type.

impl<D, MGD> PaddingScheme for Oaep<D, MGD>

where D: Digest + FixedOutputReset, MGD: Digest + FixedOutputReset,

fn decrypt<Rng>( self, rng: Option<&mut Rng>, priv_key: &RsaPrivateKey, ciphertext: &[u8], ) -> Result<Vec<u8>, Error>

where Rng: TryCryptoRng + ?Sized,

Decrypt the given message using the given private key.

fn encrypt<Rng>( self, rng: &mut Rng, pub_key: &RsaPublicKey, msg: &[u8], ) -> Result<Vec<u8>, Error>

where Rng: TryCryptoRng + ?Sized,

Encrypt the given message using the given public key.