crypto: chacha20poly1305 - Skip encryption/decryption for 0-len

If the length of the plaintext is zero, there's no need to waste cycles
on encryption and decryption. Using the chacha20poly1305 construction
for zero-length plaintexts is a common way of using a shared encryption
key for AAD authentication.

Signed-off-by: Jason A. Donenfeld <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
1 file changed