.It Fa key
A 32-byte secret key.
.It Fa nonce
-An 8 or 24 byte number, used only once with any given key.
+An 8-byte or 24-byte number, used only once with any given key.
It does not need to be secret or random, but it does have to be unique.
Repeating a nonce with the same key reveals the XOR of two different
messages, which allows decryption.
-24 byte nonces can be selected at random.
-8 byte nonces
+24-byte nonces can be selected at random.
+8-byte nonces
.Em cannot .
They are too small, and the same number may be selected twice by
accident.
initialises the
.Vt crypto_chacha_ctx
context.
-It uses an 8 byte nonce, too small to be selected at random.
+It uses an 8-byte nonce, too small to be selected at random.
Use a counter.
.Pp
.Fn crypto_chacha20_x_init
.Xr crypto_lock 3monocypher
family of functions.
.It Fa your_secret_key
-A 32 byte random number, known only to you.
+A 32-byte random number, known only to you.
See
.Xr intro 3monocypher
for advice about generating random bytes (use the operating system's
with
.Fn crypto_x25519_public_key .
.It Fa secret_key
-A 32 byte random number, known only to you.
+A 32-byte random number, known only to you.
.El
.Sh RETURN VALUES
Some public keys force the shared key to a known constant.
The arguments are:
.Bl -tag -width Ds
.It Fa secret_key
-A 32 byte random number, known only to you.
+A 32-byte random number, known only to you.
See
.Xr intro 3monocypher
about random number generation (use your operating system's random
.Xr crypto_blake2b 3monocypher
first.
.It Fa your_secret_key
-A 32 byte secret random number.
+A 32-byte secret random number.
See
.Xr intro 3monocypher
for advice about generating random bytes (use the operating system's