# Trait kernel::hil::public_key_crypto::rsa_math::RsaCryptoBase

source · ```
pub trait RsaCryptoBase<'a> {
// Required methods
fn set_client(&'a self, client: &'a dyn Client<'a>);
fn clear_data(&self);
fn mod_exponent(
&self,
message: &'static mut [u8],
modulus: &'static [u8],
exponent: &'static [u8],
result: &'static mut [u8]
) -> Result<(), (ErrorCode, &'static mut [u8], &'static [u8], &'static [u8], &'static mut [u8])>;
}
```

## Required Methods§

source#### fn set_client(&'a self, client: &'a dyn Client<'a>)

#### fn set_client(&'a self, client: &'a dyn Client<'a>)

Set the `Client`

client to be called on completion.

source#### fn clear_data(&self)

#### fn clear_data(&self)

Clear any confidential data.

source#### fn mod_exponent(
&self,
message: &'static mut [u8],
modulus: &'static [u8],
exponent: &'static [u8],
result: &'static mut [u8]
) -> Result<(), (ErrorCode, &'static mut [u8], &'static [u8], &'static [u8], &'static mut [u8])>

#### fn mod_exponent( &self, message: &'static mut [u8], modulus: &'static [u8], exponent: &'static [u8], result: &'static mut [u8] ) -> Result<(), (ErrorCode, &'static mut [u8], &'static [u8], &'static [u8], &'static mut [u8])>

Calculate (`message`

^ `exponent`

) % `modulus`

and store it in the
`result`

buffer.

On completion the `mod_exponent_done()`

upcall will be scheduled.

The length of `modulus`

must be a power of 2 and determines the length
of the operation.

The `message`

and `exponent`

buffers can be any length. All of the data
in the buffer up to the length of the `modulus`

will be used. This
allows callers to allocate larger buffers to support multiple
RSA lengths, but only the operation length (defined by the modulus)
will be used.

The `result`

buffer must be at least as large as the `modulus`

buffer,
otherwise Err(SIZE) will be returned.
If `result`

is longer then `modulus`

the data will be stored in the
`result`

buffer from 0 to `modulue.len()`

.

The possible ErrorCodes are:

- BUSY: An operation is already on going
- INVAL: An invalid parameter was supplied
- SIZE: The size of the
`result`

buffer is invalid - NOSUPPORT: The operation is not supported