X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=tfc_error.c;h=2108dc519a02a1822a305355c546ec39fe9526f8;hb=a2ba0ca55c0bccf3695f9fdfacfbd991a2a73cf1;hp=16e4cd0352010ced823d281de6fb6e3d7ac987f5;hpb=1a8928c3ab5bd19851a3d2d03451b2f8a25c62e9;p=tfcrypt.git

diff --git a/tfc_error.c b/tfc_error.c
index 16e4cd0..2108dc5 100644
--- a/tfc_error.c
+++ b/tfc_error.c
@@ -91,11 +91,14 @@ void usage(void)
 	tfc_yesno is_embedded_prog = NO;
 
 	if (optopt == 'V') {
-		char shash[64];
 		tfc_say("tfcrypt toolkit, version %s.", _TFCRYPT_VERSION);
-		hash_defaults(shash, sizeof(shash));
-		tfc_say("Defaults hash: %s", shash);
-		memset(shash, 0, sizeof(shash));
+		if (ctr_mode != TFC_MODE_PLAIN) {
+			char shash[64];
+
+			hash_defaults(shash, sizeof(shash));
+			tfc_say("Defaults hash: %s", shash);
+			memset(shash, 0, sizeof(shash));
+		}
 		xexit(0);
 	}
 
@@ -266,7 +269,11 @@ void usage(void)
 	tfc_say("    -: read a detached MAC signature from stdin,");
 	tfc_say("    drop: do not verify attached MAC, if any, and drop it from output.");
 	tfc_say("  -m: just verify MAC provided with -M. Do not write output file.");
-	tfc_say("    This option must be specified after -M.");
+	tfc_say("  -u: almost same as -m, but turns on MAC pre-test mode, when verified");
+	tfc_say("    signature enables writing output file. It is useful when decrypting small texts.");
+	tfc_say("    The source must be a seekable file, otherwise this mode will be disabled.");
+	tfc_say("    In this mode, decryption is done twice and verification done once.");
+	tfc_say("    Both -m and -u options must be specified after -M.");
 	tfc_say("  -E how: how to behave on I/O errors (both src or dst):");
 	tfc_say("    exit: print error if not quiet, then exit,");
 	tfc_say("    cont: print error if not quiet, then continue,");