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use crate::utils::*;
use botan_sys::*;
#[derive(Debug)]
/// A raw block cipher interface (ie ECB mode)
///
/// Warning: you almost certainly want an AEAD cipher mode instead
pub struct BlockCipher {
obj: botan_block_cipher_t,
block_size: usize,
min_keylen: usize,
max_keylen: usize,
mod_keylen: usize,
}
impl Drop for BlockCipher {
fn drop(&mut self) {
unsafe {
botan_block_cipher_destroy(self.obj);
}
}
}
impl BlockCipher {
/// Create a new block cipher instance, failing if the cipher is unknown
///
/// # Examples
///
/// ```
/// let cipher = botan::BlockCipher::new("AES-128");
/// assert!(cipher.is_ok());
/// let no_such_cipher = botan::BlockCipher::new("SuperCipher9000");
/// assert!(no_such_cipher.is_err());
/// ```
pub fn new(name: &str) -> Result<BlockCipher> {
let mut obj = ptr::null_mut();
call_botan! { botan_block_cipher_init(&mut obj, make_cstr(name)?.as_ptr()) };
let block_size = unsafe { botan_block_cipher_block_size(obj) };
if block_size < 0 {
return Err(Error::from(block_size));
}
let mut min_keylen = 0;
let mut max_keylen = 0;
let mut mod_keylen = 0;
call_botan! { botan_block_cipher_get_keyspec(obj, &mut min_keylen, &mut max_keylen, &mut mod_keylen) };
Ok(BlockCipher {
obj,
block_size: block_size as usize,
min_keylen,
max_keylen,
mod_keylen,
})
}
/// Return the block size of the cipher, in bytes
///
/// # Examples
///
/// ```
/// let cipher = botan::BlockCipher::new("AES-128").unwrap();
/// assert_eq!(cipher.block_size().unwrap(), 16);
/// ```
pub fn block_size(&self) -> Result<usize> {
Ok(self.block_size)
}
/// Return the name of this algorithm which may or may not exactly
/// match what was provided to new()
///
/// # Examples
///
/// ```
/// let cipher = botan::BlockCipher::new("AES-128").unwrap();
/// assert_eq!(cipher.algo_name().unwrap(), "AES-128");
/// ```
pub fn algo_name(&self) -> Result<String> {
call_botan_ffi_returning_string(32, &|out_buf, out_len| unsafe {
botan_block_cipher_name(self.obj, out_buf as *mut c_char, out_len)
})
}
/// Return information about the key lengths supported by this object
pub fn key_spec(&self) -> Result<KeySpec> {
KeySpec::new(self.min_keylen, self.max_keylen, self.mod_keylen)
}
/// Set the key for the cipher.
///
/// # Errors
///
/// Fails if the key is not a valid length for the cipher
///
/// # Examples
///
/// ```
/// let cipher = botan::BlockCipher::new("AES-128").unwrap();
/// assert!(cipher.set_key(&vec![0; 32]).is_err());
/// assert!(cipher.set_key(&vec![0; 16]).is_ok());
/// ```
pub fn set_key(&self, key: &[u8]) -> Result<()> {
call_botan! { botan_block_cipher_set_key(self.obj, key.as_ptr(), key.len()) };
Ok(())
}
/// Encrypt some blocks of data
///
/// # Errors
///
/// Fails if the input is not a multiple of the block size, or if the
/// key was not set on the object.
///
/// # Examples
///
/// ```
/// let cipher = botan::BlockCipher::new("AES-128").unwrap();
/// // Key is not set
/// assert!(cipher.encrypt_blocks(&vec![0; 16]).is_err());
/// assert!(cipher.set_key(&vec![0; 16]).is_ok());
/// // Not a multiple of block size
/// assert!(cipher.encrypt_blocks(&vec![0; 17]).is_err());
/// // Key is set and multiple of block size - ok
/// assert!(cipher.encrypt_blocks(&vec![0; 16]).is_ok());
/// ```
pub fn encrypt_blocks(&self, input: &[u8]) -> Result<Vec<u8>> {
if input.len() % self.block_size != 0 {
return Err(Error::InvalidInput);
}
let blocks = input.len() / self.block_size;
let mut output = vec![0; input.len()];
call_botan! { botan_block_cipher_encrypt_blocks(self.obj, input.as_ptr(), output.as_mut_ptr(), blocks) };
Ok(output)
}
/// Encrypt in place
pub fn encrypt_in_place(&self, buf: &mut [u8]) -> Result<()> {
if buf.len() % self.block_size != 0 {
return Err(Error::InvalidInput);
}
let blocks = buf.len() / self.block_size;
call_botan! { botan_block_cipher_encrypt_blocks(self.obj, buf.as_ptr(), buf.as_mut_ptr(), blocks) };
Ok(())
}
/// Decrypt some blocks of data
///
/// # Errors
///
/// Fails if the input is not a multiple of the block size, or if the
/// key was not set on the object.
///
/// # Examples
///
/// ```
/// let cipher = botan::BlockCipher::new("AES-128").unwrap();
/// // Key is not set
/// assert!(cipher.decrypt_blocks(&vec![0; 16]).is_err());
/// assert!(cipher.set_key(&vec![0; 16]).is_ok());
/// // Not a multiple of block size
/// assert!(cipher.decrypt_blocks(&vec![0; 17]).is_err());
/// // Key is set and multiple of block size - ok
/// assert!(cipher.decrypt_blocks(&vec![0; 16]).is_ok());
/// ```
pub fn decrypt_blocks(&self, input: &[u8]) -> Result<Vec<u8>> {
if input.len() % self.block_size != 0 {
return Err(Error::InvalidInput);
}
let blocks = input.len() / self.block_size;
let mut output = vec![0; input.len()];
call_botan! { botan_block_cipher_decrypt_blocks(self.obj, input.as_ptr(), output.as_mut_ptr(), blocks) };
Ok(output)
}
/// Decrypt in place
pub fn decrypt_in_place(&self, buf: &mut [u8]) -> Result<()> {
if buf.len() % self.block_size != 0 {
return Err(Error::InvalidInput);
}
let blocks = buf.len() / self.block_size;
call_botan! { botan_block_cipher_decrypt_blocks(self.obj, buf.as_ptr(), buf.as_mut_ptr(), blocks) };
Ok(())
}
/// Clear the key set on the cipher from memory. After this, the
/// object is un-keyed and must be re-keyed before use.
///
/// # Examples
///
/// ```
/// let cipher = botan::BlockCipher::new("AES-128").unwrap();
/// assert!(cipher.set_key(&vec![0; 16]).is_ok());
/// assert!(cipher.encrypt_blocks(&vec![0; 16]).is_ok());
/// assert!(cipher.clear().is_ok());
/// assert!(cipher.encrypt_blocks(&vec![0; 16]).is_err());
/// ```
pub fn clear(&self) -> Result<()> {
call_botan! { botan_block_cipher_clear(self.obj) };
Ok(())
}
}