Clarify Tag Length Setting in OCB Mode

Fixes #8331: Updated the description for setting the tag length in OCB mode to remove the misleading “when encrypting” and “during encryption” phrasing. This change emphasizes that setting a custom tag length requires a call with NULL, applicable to both encryption and decryption contexts.

Reviewed-by: Frederik Wedel-Heinen <fwh.openssl@gmail.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25424)

(cherry picked from commit 1299699a90)
This commit is contained in:
erbsland-dev 2024-09-10 19:20:17 +02:00 committed by Tomas Mraz
parent 0e767cfe00
commit c60e6d91ed
1 changed files with 3 additions and 4 deletions

View File

@ -1434,10 +1434,9 @@ For GCM, this call is only valid when decrypting data.
For OCB, this call is valid when decrypting data to set the expected tag,
and when encrypting to set the desired tag length.
In OCB mode, calling this when encrypting with C<tag> set to C<NULL> sets the
tag length. The tag length can only be set before specifying an IV. If this is
not called prior to setting the IV during encryption, then a default tag length
is used.
In OCB mode, calling this with C<tag> set to C<NULL> sets the tag length.
The tag length can only be set before specifying an IV. If this is not called
prior to setting the IV, then a default tag length is used.
For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the
maximum tag length for OCB.