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authorAndrzej Kurek <andrzej.kurek@arm.com>2020-07-15 08:50:59 -0400
committerAndrzej Kurek <andrzej.kurek@arm.com>2020-07-17 03:28:32 -0400
commita9a5ff5f313a4832227de50f0cd21268cf415bc6 (patch)
treef67a0fcd854b3424beec117fd0e7809733a0a767
parent11ddf25828adce96dc7a9cf259b34a19f912f190 (diff)
downloadmbed-tls-a9a5ff5f313a4832227de50f0cd21268cf415bc6.tar.gz
aes: add a comment about expected keybits value.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
-rw-r--r--library/aes.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/library/aes.c b/library/aes.c
index c4710c45c..e9e754449 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -725,6 +725,8 @@ int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
return( mbedtls_aesni_setkey_enc( (unsigned char *) ctx->rk, key, keybits ) );
#endif
+ /* Three least significant bits are truncated from keybits, which is
+ * expected to be a multiple of 8. */
mbedtls_platform_memset( RK, 0, keybits >> 3 );
offset = mbedtls_platform_random_in_range( keybits >> 5 );