diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index 0977cab..8270009 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -808,9 +808,15 @@
     transform->ivlen       = traffic_keys->iv_len;
     transform->maclen      = 0;
     transform->fixed_ivlen = transform->ivlen;
-    transform->minlen      = transform->taglen + 1;
     transform->minor_ver   = MBEDTLS_SSL_MINOR_VERSION_4;
 
+    /* We add the true record content type (1 Byte) to the plaintext and
+     * then pad to the configured granularity. The mimimum length of the
+     * type-extended and padded plaintext is therefore the padding
+     * granularity. */
+    transform->minlen =
+        transform->taglen + MBEDTLS_SSL_TLS1_3_PADDING_GRANULARITY;
+
     return( 0 );
 }