Struct Writer 

pub struct Writer<W, const CHUNK: usize> { /* private fields */ }

Available on crate features allow-non-fips and std only.

A wrapper for any implementor of std::io::Write.

Writer implements std::io::Write and takes a child which also implements this trait. This type can wrap any writer, and ensure all data passed to said writer is encrypted.

Implementations

impl<W, const CHUNK: usize> Writer<W, CHUNK>

pub const fn new(chacha: ChaCha20<Streaming>, writer: W) -> Result<Self, W>

Creates a new Writer instance.

Arguments

• chacha - The ChaCha20 instance in streaming mode.
• writer - The underlying writer.

Returns

A new Writer instance.

Errors

If the size of CHUNK is greater than u32::MAX

pub fn finish(self) -> ChaCha20<NeedsIv>

Finishes the streaming encryption and returns to the NeedsIv state.

Returns

A ChaCha20 instance in the NeedsIv state.

Methods from Deref<Target = ChaCha20<Streaming>>

pub fn decrypt_into( &mut self, cipher: &[u8], plain: &mut [u8], ) -> Result<(), Unspecified>

Decrypts the ciphertext into the output buffer.

Arguments

• cipher - The ciphertext to decrypt.
• plain - The buffer to store the decrypted data.

Errors

• If the length of cipher is greater than u32::MAX.
• If the length of cipher is greater than the length of plain.

pub fn decrypt_in_place<'io>( &mut self, in_out: &'io mut [u8], ) -> Result<&'io [u8], Unspecified>

Decrypts the ciphertext in-place.

Arguments

• in_out - The plaintext to decrypt in place.

Errors

If the length of in_out is greater than u32::MAX.

Returns

The in_out argument, decrypted, for convenience. This can be ignored.

pub fn decrypt_into_sized<const I: usize, const O: usize>( &mut self, cipher: &[u8; I], plain: &mut [u8; O], ) -> Result<(), Unspecified>

Decrypts the ciphertext into the output buffer with compile-time safety checks.

Arguments

• cipher - The ciphertext array to decrypt.
• plain - The array to store the decrypted data.

Errors

• If the length of cipher is greater than u32::MAX.
• If the length of cipher is greater than the length of plain.

pub fn decrypt_in_place_sized<'io, const C: usize>( &mut self, in_out: &'io mut [u8; C], ) -> Result<&'io [u8; C], Unspecified>

Decrypts the ciphertext in-place with compile-time safety checks.

Arguments

• in_out - The ciphertext to decrypt in-place.

Returns

ChaCha20 instance in the NeedsIv state.

Errors

• The length of in_out was greater than u32::MAX.

pub fn decrypt_into_exact<const C: usize>( &mut self, cipher: &[u8; C], plain: &mut [u8; C], ) -> Result<(), Unspecified>

Decrypts the ciphertext into the output buffer with exact sizes.

Arguments

• cipher - The ciphertext array to decrypt.
• plain - The array to store the decrypted data.

Errors

If C (the length of cipher and plain) is greater than u32::MAX.

pub fn decrypt(&mut self, cipher: &[u8]) -> Result<Vec<u8>, Unspecified>

Available on crate feature alloc only.

Decrypts the ciphertext and returns the plaintext as a vector.

Arguments

• cipher - The ciphertext to decrypt.

Errors

If the length of cipher is greater than u32::MAX.

Returns

A newly allocated buffer, the same length as cipher, containing the decrypted plaintext.

pub fn decrypt_exact<const O: usize>( &mut self, cipher: &[u8; O], ) -> Result<[u8; O], Unspecified>

Decrypts the ciphertext array and returns the plaintext array.

Arguments

• cipher - The ciphertext array to decrypt.

Errors

If O (the length of cipher) is greater than u32::MAX.

pub fn encrypt_into( &mut self, plain: &[u8], cipher: &mut [u8], ) -> Result<(), Unspecified>

Encrypts the input into the output buffer in streaming mode.

Arguments

• plain - The input to encrypt.
• cipher - The buffer to store the encrypted data.

Errors

• The length of cipher is less than the length of plain.
• The length of plain is greater than u32::MAX.

pub fn encrypt_into_sized<const I: usize, const O: usize>( &mut self, plain: &[u8; I], cipher: &mut [u8; O], ) -> Result<(), Unspecified>

Encrypts the input into the output buffer in streaming mode with compile-time size checking.

Arguments

• plain - The input array to encrypt.
• cipher - The array to store the encrypted data.

Errors

• The length of plain was greater than u32::MAX.
• The length of cipher was less than the length of plain.

pub fn encrypt_into_exact<const C: usize>( &mut self, input: &[u8; C], output: &mut [u8; C], ) -> Result<(), Unspecified>

Encrypts the input into the output buffer in streaming mode with exact sizes.

Type Parameters

• C - The size of both the input and output arrays.

Arguments

• input - The input array to encrypt.
• output - The array to store the encrypted data.

Errors

C (the length of input and output) was greater than u32::MAX.

Trait Implementations

impl<W, const CHUNK: usize> Deref for Writer<W, CHUNK>

type Target = ChaCha20<Streaming>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<W, const CHUNK: usize> DerefMut for Writer<W, CHUNK>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<W: Write, const CHUNK: usize> Write for Writer<W, CHUNK>

fn write(&mut self, buf: &[u8]) -> Result<usize>

Encrypts and writes the given buffer.

Arguments

• buf - The buffer to encrypt and write.

Returns

The number of bytes written on success, or an io::Error on failure.

Note

The maximum number of bytes this can write in a single invocation is capped by the CHUNK size. If this is not desirable, please consider using the write_all implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<()>

Encrypts and writes the entire buffer.

Arguments

• buf - The buffer to encrypt and write.

Returns

Ok(()) on success, or an io::Error on failure.

fn flush(&mut self) -> Result<()>

Flushes the underlying writer.

Returns

Propagates the result of invoking flush for the underlying writer

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.