diff --git a/src/utils/common.c b/src/utils/common.c
index 99861aeba..c814e89a7 100644
--- a/src/utils/common.c
+++ b/src/utils/common.c
@@ -344,6 +344,135 @@ TCHAR * wpa_strdup_tchar(const char *str)
 #endif /* CONFIG_NATIVE_WINDOWS */
 
 
+void printf_encode(char *txt, size_t maxlen, const u8 *data, size_t len)
+{
+	char *end = txt + maxlen;
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		if (txt + 4 > end)
+			break;
+
+		switch (data[i]) {
+		case '\"':
+			*txt++ = '\\';
+			*txt++ = '\"';
+			break;
+		case '\\':
+			*txt++ = '\\';
+			*txt++ = '\\';
+			break;
+		case '\e':
+			*txt++ = '\\';
+			*txt++ = 'e';
+			break;
+		case '\n':
+			*txt++ = '\\';
+			*txt++ = 'n';
+			break;
+		case '\r':
+			*txt++ = '\\';
+			*txt++ = 'r';
+			break;
+		case '\t':
+			*txt++ = '\\';
+			*txt++ = 't';
+			break;
+		default:
+			if (data[i] >= 32 && data[i] <= 127) {
+				*txt++ = data[i];
+			} else {
+				txt += os_snprintf(txt, end - txt, "\\x%02x",
+						   data[i]);
+			}
+			break;
+		}
+	}
+
+	*txt = '\0';
+}
+
+
+size_t printf_decode(u8 *buf, size_t maxlen, const char *str)
+{
+	const char *pos = str;
+	size_t len = 0;
+	int val;
+
+	while (*pos) {
+		if (len == maxlen)
+			break;
+		switch (*pos) {
+		case '\\':
+			pos++;
+			switch (*pos) {
+			case '\\':
+				buf[len++] = '\\';
+				pos++;
+				break;
+			case '"':
+				buf[len++] = '"';
+				pos++;
+				break;
+			case 'n':
+				buf[len++] = '\n';
+				pos++;
+				break;
+			case 'r':
+				buf[len++] = '\r';
+				pos++;
+				break;
+			case 't':
+				buf[len++] = '\t';
+				pos++;
+				break;
+			case 'e':
+				buf[len++] = '\e';
+				pos++;
+				break;
+			case 'x':
+				pos++;
+				val = hex2byte(pos);
+				if (val < 0) {
+					val = hex2num(*pos);
+					if (val < 0)
+						break;
+					buf[len++] = val;
+					pos++;
+				} else {
+					buf[len++] = val;
+					pos += 2;
+				}
+				break;
+			case '0':
+			case '1':
+			case '2':
+			case '3':
+			case '4':
+			case '5':
+			case '6':
+			case '7':
+				val = *pos++ - '0';
+				if (*pos >= '0' && *pos <= '7')
+					val = val * 8 + (*pos++ - '0');
+				if (*pos >= '0' && *pos <= '7')
+					val = val * 8 + (*pos++ - '0');
+				buf[len++] = val;
+				break;
+			default:
+				break;
+			}
+			break;
+		default:
+			buf[len++] = *pos++;
+			break;
+		}
+	}
+
+	return len;
+}
+
+
 /**
  * wpa_ssid_txt - Convert SSID to a printable string
  * @ssid: SSID (32-octet string)
diff --git a/src/utils/common.h b/src/utils/common.h
index 7f115efe8..fbc61191e 100644
--- a/src/utils/common.h
+++ b/src/utils/common.h
@@ -441,6 +441,9 @@ TCHAR * wpa_strdup_tchar(const char *str);
 #define wpa_strdup_tchar(s) strdup((s))
 #endif /* CONFIG_NATIVE_WINDOWS */
 
+void printf_encode(char *txt, size_t maxlen, const u8 *data, size_t len);
+size_t printf_decode(u8 *buf, size_t maxlen, const char *str);
+
 const char * wpa_ssid_txt(const u8 *ssid, size_t ssid_len);
 
 static inline int is_zero_ether_addr(const u8 *a)
diff --git a/tests/.gitignore b/tests/.gitignore
index 39c7447fd..bef38cfa9 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -7,6 +7,7 @@ test-md4
 test-md5
 test-milenage
 test-ms_funcs
+test-printf
 test-rc4
 test-sha1
 test-sha256
diff --git a/tests/Makefile b/tests/Makefile
index 0774337e7..d49633084 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -1,4 +1,6 @@
-TESTS=test-base64 test-md4 test-md5 test-milenage test-ms_funcs test-sha1 \
+TESTS=test-base64 test-md4 test-md5 test-milenage test-ms_funcs \
+	test-printf \
+	test-sha1 \
 	test-sha256 test-aes test-asn1 test-x509 test-x509v3 test-list test-rc4
 
 all: $(TESTS)
@@ -63,6 +65,9 @@ test-milenage: test-milenage.o $(LIBS)
 test-ms_funcs: test-ms_funcs.o $(LIBS)
 	$(LDO) $(LDFLAGS) -o $@ $^
 
+test-printf: test-printf.o $(LIBS)
+	$(LDO) $(LDFLAGS) -o $@ $^
+
 test-rc4: test-rc4.o $(LIBS)
 	$(LDO) $(LDFLAGS) -o $@ $^
 
@@ -85,6 +90,7 @@ run-tests: $(TESTS)
 	./test-md4
 	./test-md5
 	./test-milenage
+	./test-printf
 	./test-sha1
 	./test-sha256
 	@echo
diff --git a/tests/test-printf.c b/tests/test-printf.c
new file mode 100644
index 000000000..a8a2e258e
--- /dev/null
+++ b/tests/test-printf.c
@@ -0,0 +1,83 @@
+/*
+ * printf format routines - test program
+ * Copyright (c) 2012, Jouni Malinen <j@w1.fi>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "utils/includes.h"
+#include "utils/os.h"
+#include "utils/common.h"
+
+
+struct test_data {
+	u8 *data;
+	size_t len;
+	char *encoded;
+};
+
+static const struct test_data tests[] = {
+	{ (u8 *) "abcde", 5, "abcde" },
+	{ (u8 *) "a\0b\nc\ed\re\tf", 11, "a\\0b\\nc\\ed\\re\\tf" },
+	{ (u8 *) "\x00\x31\x00\x32\x00\x39", 6, "\\x001\\0002\\09" },
+	{ (u8 *) "\n\n\n", 3, "\n\12\x0a" },
+	{ (u8 *) "\303\245\303\244\303\266\303\205\303\204\303\226", 12,
+	  "\\xc3\\xa5\xc3\\xa4\\xc3\\xb6\\xc3\\x85\\xc3\\x84\\xc3\\x96" },
+	{ (u8 *) "\303\245\303\244\303\266\303\205\303\204\303\226", 12,
+	  "\\303\\245\\303\\244\\303\\266\\303\\205\\303\\204\\303\\226" },
+	{ (u8 *) "\xe5\xe4\xf6\xc5\xc4\xd6", 6,
+	  "\\xe5\\xe4\\xf6\\xc5\\xc4\\xd6" },
+	{ NULL, 0, NULL }
+};
+
+
+static void print_hex(const u8 *data, size_t len)
+{
+	size_t i;
+	for (i = 0; i < len; i++)
+		printf(" %02x", data[i]);
+}
+
+
+int main(int argc, char *argv[])
+{
+	int i;
+	size_t binlen;
+	char buf[100];
+	u8 bin[100];
+	int errors = 0;
+
+	for (i = 0; tests[i].data; i++) {
+		const struct test_data *test = &tests[i];
+		printf("%d:", i);
+		print_hex(test->data, test->len);
+		printf_encode(buf, sizeof(buf), test->data, test->len);
+		printf(" -> \"%s\"\n", buf);
+
+		binlen = printf_decode(bin, sizeof(bin), buf);
+		if (binlen != test->len ||
+		    os_memcmp(bin, test->data, binlen) != 0) {
+			printf("Error in decoding#1:");
+			print_hex(bin, binlen);
+			printf("\n");
+			errors++;
+		}
+
+		binlen = printf_decode(bin, sizeof(bin), test->encoded);
+		if (binlen != test->len ||
+		    os_memcmp(bin, test->data, binlen) != 0) {
+			printf("Error in decoding#2:");
+			print_hex(bin, binlen);
+			printf("\n");
+			errors++;
+		}
+	}
+
+	if (errors) {
+		printf("%d test(s) failed\n", errors);
+		return -1;
+	}
+
+	return 0;
+}