libsodium_crypto_secretbox_xsalsa20poly1305 (libsodium v3.0.1)
View SourceThe NaCl XSalsa20-Poly1305 secret box primitive behind
libsodium_crypto_secretbox.
Only the NaCl padded interface is available here: the plaintext passed to
crypto_secretbox_xsalsa20poly1305/3 must start with zerobytes/0 zero
bytes, and the ciphertext starts with boxzerobytes/0 zero bytes
followed by the macbytes/0 byte tag. Keys are keybytes/0 bytes and
nonces noncebytes/0 bytes; a nonce must never be reused with the same
key. Prefer libsodium_crypto_secretbox:easy/3 in new code.
Key = libsodium_crypto_secretbox_xsalsa20poly1305:keygen(),
Nonce = libsodium_randombytes:buf(libsodium_crypto_secretbox_xsalsa20poly1305:noncebytes()),
Padded = <<0:256, "message">>,
Boxed = libsodium_crypto_secretbox_xsalsa20poly1305:crypto_secretbox_xsalsa20poly1305(Padded, Nonce, Key),
<<0:128, _Tag:16/binary, _Ciphertext:7/binary>> = Boxed,
Padded = libsodium_crypto_secretbox_xsalsa20poly1305:open(Boxed, Nonce, Key).Summary
Types
A crypto_secretbox_xsalsa20poly1305_KEYBYTES (32-byte) binary.
A crypto_secretbox_xsalsa20poly1305_NONCEBYTES (24-byte) binary.
Functions
Return crypto_secretbox_xsalsa20poly1305_boxzerobytes(), in bytes.
Encrypt M, which must start with zerobytes/0 zero bytes, with the
noncebytes/0 byte nonce N and the keybytes/0 byte key K.
Return crypto_secretbox_xsalsa20poly1305_keybytes(), in bytes.
Generate a random keybytes/0 byte key.
Return crypto_secretbox_xsalsa20poly1305_macbytes(), in bytes.
Return crypto_secretbox_xsalsa20poly1305_messagebytes_max(), in bytes.
Return crypto_secretbox_xsalsa20poly1305_noncebytes(), in bytes.
Verify and decrypt C, which must start with boxzerobytes/0 zero
bytes, with the nonce N and key K.
Return crypto_secretbox_xsalsa20poly1305_zerobytes(), in bytes.
Types
Functions
-spec boxzerobytes() -> Result when Result :: 16.
Return crypto_secretbox_xsalsa20poly1305_boxzerobytes(), in bytes.
-spec crypto_secretbox_xsalsa20poly1305(M, N, K) -> Result when M :: binary(), N :: n(), K :: k(), Result :: binary() | -1.
Encrypt M, which must start with zerobytes/0 zero bytes, with the
noncebytes/0 byte nonce N and the keybytes/0 byte key K.
Returns a ciphertext of the same length as M that starts with
boxzerobytes/0 zero bytes, followed by the authentication tag and
the encrypted message, or -1 when M is shorter than
zerobytes/0. Non-zero padding bytes leak the authentication key.
-spec keybytes() -> Result when Result :: 32.
Return crypto_secretbox_xsalsa20poly1305_keybytes(), in bytes.
-spec keygen() -> Result when Result :: k().
Generate a random keybytes/0 byte key.
-spec macbytes() -> Result when Result :: 16.
Return crypto_secretbox_xsalsa20poly1305_macbytes(), in bytes.
-spec messagebytes_max() -> Result when Result :: non_neg_integer().
Return crypto_secretbox_xsalsa20poly1305_messagebytes_max(), in bytes.
-spec noncebytes() -> Result when Result :: 24.
Return crypto_secretbox_xsalsa20poly1305_noncebytes(), in bytes.
Verify and decrypt C, which must start with boxzerobytes/0 zero
bytes, with the nonce N and key K.
Returns a plaintext of the same length as C that starts with
zerobytes/0 zero bytes, or -1 when verification fails or C is
shorter than zerobytes/0.
-spec zerobytes() -> Result when Result :: 32.
Return crypto_secretbox_xsalsa20poly1305_zerobytes(), in bytes.