crypto_blake2b: Harmonize description with MAC example

diff --git a/doc/man/man3/crypto_blake2b.3monocypher b/doc/man/man3/crypto_blake2b.3monocypher
index 5ff809f77a3c0cc8645171efd9fa67e45dc9c53e..620829971e49844334fedc0baf3b29915c7e71e0 100644 (file)
--- a/doc/man/man3/crypto_blake2b.3monocypher
+++ b/doc/man/man3/crypto_blake2b.3monocypher
@@ -50,7 +50,7 @@
 .\" with this software.  If not, see
 .\" <https://creativecommons.org/publicdomain/zero/1.0/>
 .\"
-.Dd March 2, 2020
+.Dd March 31, 2020
 .Dt CRYPTO_BLAKE2B 3MONOCYPHER
 .Os
 .Sh NAME
@@ -124,7 +124,10 @@ Length of
 in bytes.
 Must be between 1 and 64.
 64 is recommended.
-Anything below 32 is discouraged.
+Anything below 32 is discouraged when using Blake2b as a general-purpose
+hash function;
+anything below 16 is discouraged when using Blake2b as a message
+authentication code.
 .It Fa key
 Some secret key.
 One cannot predict the final hash without it.