diff --git a/components/common/uuid/uuid.c b/components/common/uuid/uuid.c
index 7ce46c2..5d46441 100644
--- a/components/common/uuid/uuid.c
+++ b/components/common/uuid/uuid.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2020-2021, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -7,80 +7,101 @@
 #include "uuid.h"
 #include <string.h>
 #include <ctype.h>
-#include <stdio.h>
+
+static uint8_t hex_to_nibble(char hex)
+{
+	uint8_t nibble = 0;
+
+	if (hex >= '0' && hex <= '9') {
+		nibble = hex - '0';
+	}
+	else {
+		nibble = ((hex | 0x20) - 'a') + 10;
+	}
+
+	return nibble;
+}
+
+static uint8_t hex_to_byte(const char *hex)
+{
+	/* Takes a validated input and returns the byte value */
+	uint8_t byte = hex_to_nibble(hex[0]) << 4;
+	byte |= (hex_to_nibble(hex[1]) & 0x0f);
+	return byte;
+}
 
 size_t uuid_is_valid(const char *canonical_form)
 {
-    size_t valid_chars = 0;
-    size_t input_len = strlen(canonical_form);
+	size_t valid_chars = 0;
+	size_t input_len = strlen(canonical_form);
 
-    if (input_len >= UUID_CANONICAL_FORM_LEN) {
+	if (input_len >= UUID_CANONICAL_FORM_LEN) {
 
-        size_t i;
-        valid_chars = UUID_CANONICAL_FORM_LEN;
+		size_t i;
+		valid_chars = UUID_CANONICAL_FORM_LEN;
 
-        for (i = 0; i < UUID_CANONICAL_FORM_LEN; ++i) {
+		for (i = 0; i < UUID_CANONICAL_FORM_LEN; ++i) {
 
-            if (i == 8 || i == 13 || i == 18 || i == 23) {
-                if (canonical_form[i] != '-') return 0;
-            }
-            else {
-                if (!isxdigit(canonical_form[i])) return 0;
-            }
-        }
-    }
+			if (i == 8 || i == 13 || i == 18 || i == 23) {
+				if (canonical_form[i] != '-') return 0;
+			}
+			else {
+				if (!isxdigit(canonical_form[i])) return 0;
+			}
+		}
+	}
 
-    return valid_chars;
+	return valid_chars;
 }
 
 size_t uuid_parse_to_octets(const char *canonical_form, uint8_t *buf, size_t buf_size)
 {
-    size_t octet_index = 0;
-    const char *pos;
-    size_t valid_chars = uuid_is_valid(canonical_form);
+	size_t octet_index = 0;
+	const char *pos;
+	size_t valid_chars = uuid_is_valid(canonical_form);
 
-    if ((buf_size < UUID_OCTETS_LEN) ||
-        (valid_chars != UUID_CANONICAL_FORM_LEN)) {
-        /* Invalid input */
-        return 0;
-    }
+	if ((buf_size < UUID_OCTETS_LEN) ||
+		(valid_chars != UUID_CANONICAL_FORM_LEN)) {
+		/* Invalid input */
+		return 0;
+	}
 
-    /*
-     * UUID string has been validates as having the following form:
-     * xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
-     *     4      2    2   2       6
-     */
-    pos = &canonical_form[0];
-    while (octet_index < 4) {
-        sscanf(pos, "%02hhX", &buf[octet_index++]);
-        pos += 2;
-    }
+	/*
+	 * UUID string has been validates as having the following form:
+	 * xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
+	 *     4      2    2   2       6
+	 */
+	pos = &canonical_form[0];
+	while (octet_index < 4) {
+		buf[octet_index++] = hex_to_byte(pos);
+		pos += 2;
+	}
 
-    pos = &canonical_form[9];
-    while (octet_index < 6) {
-        sscanf(pos, "%02hhX", &buf[octet_index++]);
-        pos += 2;
-    }
+	pos = &canonical_form[9];
+	while (octet_index < 6) {
+		buf[octet_index++] = hex_to_byte(pos);
+		pos += 2;
+	}
 
-    pos = &canonical_form[14];
-    while (octet_index < 8) {
-        sscanf(pos, "%02hhX", &buf[octet_index++]);
-        pos += 2;
-    }
+	pos = &canonical_form[14];
+	while (octet_index < 8) {
+		buf[octet_index++] = hex_to_byte(pos);
+		pos += 2;
+	}
 
-    pos = &canonical_form[19];
-    while (octet_index < 10) {
-        sscanf(pos, "%02hhX", &buf[octet_index++]);
-        pos += 2;
-    }
+	pos = &canonical_form[19];
+	while (octet_index < 10) {
+		buf[octet_index++] = hex_to_byte(pos);
+		pos += 2;
+	}
 
-    pos = &canonical_form[24];
-    while (octet_index < 16) {
-        sscanf(pos, "%02hhX", &buf[octet_index++]);
-        pos += 2;
-    }
+	pos = &canonical_form[24];
+	while (octet_index < 16) {
+		buf[octet_index++] = hex_to_byte(pos);
+		pos += 2;
+	}
 
-    return valid_chars;
+	return valid_chars;
 }
 
 /*
@@ -91,34 +112,34 @@
  */
 size_t uuid_parse_to_octets_reversed(const char *canonical_form, uint8_t *buf, size_t buf_size)
 {
-    size_t valid_chars;
-    uint8_t standard_octets[UUID_OCTETS_LEN];
+	size_t valid_chars;
+	uint8_t standard_octets[UUID_OCTETS_LEN];
 
-    valid_chars = uuid_parse_to_octets(canonical_form, standard_octets, sizeof(standard_octets));
+	valid_chars = uuid_parse_to_octets(canonical_form, standard_octets, sizeof(standard_octets));
 
-    if ((valid_chars == UUID_CANONICAL_FORM_LEN) && (buf_size >= UUID_OCTETS_LEN)) {
-        /* Reverse bytes in each section */
-        buf[0] = standard_octets[3];
-        buf[1] = standard_octets[2];
-        buf[2] = standard_octets[1];
-        buf[3] = standard_octets[0];
+	if ((valid_chars == UUID_CANONICAL_FORM_LEN) && (buf_size >= UUID_OCTETS_LEN)) {
+		/* Reverse bytes in each section */
+		buf[0] = standard_octets[3];
+		buf[1] = standard_octets[2];
+		buf[2] = standard_octets[1];
+		buf[3] = standard_octets[0];
 
-        buf[4] = standard_octets[5];
-        buf[5] = standard_octets[4];
+		buf[4] = standard_octets[5];
+		buf[5] = standard_octets[4];
 
-        buf[6] = standard_octets[7];
-        buf[7] = standard_octets[6];
+		buf[6] = standard_octets[7];
+		buf[7] = standard_octets[6];
 
-        buf[8] = standard_octets[8];
-        buf[9] = standard_octets[9];
+		buf[8] = standard_octets[8];
+		buf[9] = standard_octets[9];
 
-        buf[10] = standard_octets[10];
-        buf[11] = standard_octets[11];
-        buf[12] = standard_octets[12];
-        buf[13] = standard_octets[13];
-        buf[14] = standard_octets[14];
-        buf[15] = standard_octets[15];
-    }
+		buf[10] = standard_octets[10];
+		buf[11] = standard_octets[11];
+		buf[12] = standard_octets[12];
+		buf[13] = standard_octets[13];
+		buf[14] = standard_octets[14];
+		buf[15] = standard_octets[15];
+	}
 
-    return valid_chars;
+	return valid_chars;
 }