diff --git a/doc/tools/pkcs15-crypt.1.xml b/doc/tools/pkcs15-crypt.1.xml
index 40dd262b..5418d4b1 100644
--- a/doc/tools/pkcs15-crypt.1.xml
+++ b/doc/tools/pkcs15-crypt.1.xml
@@ -62,7 +62,8 @@
 						<option>--input</option> <replaceable>file</replaceable>,
 						<option>-i</option> <replaceable>file</replaceable>
 					</term>
-					<listitem><para>Specifies the input file to use.</para></listitem>
+					<listitem><para>Specifies the input file to use. Defaults to stdin if
+					not specified.</para></listitem>
 				</varlistentry>
 
 				<varlistentry>
@@ -78,7 +79,8 @@
 						<option>--output</option> <replaceable>file</replaceable>,
 						<option>-o</option> <replaceable>file</replaceable>
 					</term>
-					<listitem><para>Any output will be sent to the specified file.</para></listitem>
+					<listitem><para>Any output will be sent to the specified file. Defaults
+					to stdout if not specified.</para></listitem>
 				</varlistentry>
 
 				<varlistentry>
diff --git a/src/tools/pkcs15-crypt.c b/src/tools/pkcs15-crypt.c
index 9bdd2c3a..76b72737 100644
--- a/src/tools/pkcs15-crypt.c
+++ b/src/tools/pkcs15-crypt.c
@@ -88,8 +88,8 @@ static const char *option_help[] = {
 	"Decipher operation",
 	"Selects the private key ID to use",
 	"Uses reader number <arg>",
-	"Selects the input file to use",
-	"Outputs to file <arg>",
+	"Selects the input file to use (defaults to stdin)",
+	"Outputs to file <arg> (defaults to stdout)",
 	"Format for ECDSA signature <arg>: 'rs' (default), 'sequence', 'openssl'",
 	"Outputs raw 8 bit data",
 	"Input file is a SHA-1 hash",
@@ -157,13 +157,19 @@ static int read_input(u8 *buf, int buflen)
 	FILE *inf;
 	int c;
 
-	inf = fopen(opt_input, "rb");
-	if (inf == NULL) {
-		fprintf(stderr, "Unable to open '%s' for reading.\n", opt_input);
-		return -1;
+	if (opt_input==NULL) {
+		inf = stdin;
+	} else {
+		inf = fopen(opt_input, "rb");
+		if (inf == NULL) {
+			fprintf(stderr, "Unable to open '%s' for reading.\n", opt_input);
+			return -1;
+		}
 	}
 	c = fread(buf, 1, buflen, inf);
-	fclose(inf);
+	if (inf!=stdin) {
+		fclose(inf);
+	}
 	if (c < 0) {
 		perror("read");
 		return -1;
@@ -203,8 +209,7 @@ static int sign(struct sc_pkcs15_object *obj)
 	int r, c, len;
 
 	if (opt_input == NULL) {
-		fprintf(stderr, "No input file specified.\n");
-		return 2;
+		fprintf(stderr, "No input file specified. Reading from stdin\n");
 	}
 
 	c = read_input(buf, sizeof(buf));
@@ -258,8 +263,7 @@ static int decipher(struct sc_pkcs15_object *obj)
 	int r, c, len;
 
 	if (opt_input == NULL) {
-		fprintf(stderr, "No input file specified.\n");
-		return 2;
+		fprintf(stderr, "No input file specified. Reading from stdin\n");
 	}
 	c = read_input(buf, sizeof(buf));
 	if (c < 0)