Add function to rebuild certificate from compressed data

Author: pennam

src/utility/SElementArduinoCloudCertificate.cpp

@@ -14,6 +14,30 @@
 
 #include <utility/SElementArduinoCloudCertificate.h>
 
+/******************************************************************************
+ * LOCAL MODULE FUNCTIONS
+ ******************************************************************************/
+
+static void hexStringToBytes(String in, byte out[], int length) {
+  int inLength = in.length();
+  in.toUpperCase();
+  int outLength = 0;
+
+  for (int i = 0; i < inLength && outLength < length; i += 2) {
+    char highChar = in[i];
+    char lowChar = in[i + 1];
+
+    byte highByte = (highChar <= '9') ? (highChar - '0') : (highChar + 10 - 'A');
+    byte lowByte = (lowChar <= '9') ? (lowChar - '0') : (lowChar + 10 - 'A');
+
+    out[outLength++] = (highByte << 4) | (lowByte & 0xF);
+  }
+}
+
+/******************************************************************************
+ * PUBLIC MEMBER FUNCTIONS
+ ******************************************************************************/
+
 int SElementArduinoCloudCertificate::write(SecureElement & se, ECP256Certificate & cert, const SElementArduinoCloudSlot certSlot)
 {
 #if defined(SECURE_ELEMENT_IS_SE050) || defined(SECURE_ELEMENT_IS_SOFTSE)
@@ -92,3 +116,45 @@ int SElementArduinoCloudCertificate::read(SecureElement & se, ECP256Certificate
 #endif
   return 1;
 }
+
+int SElementArduinoCloudCertificate::rebuild(SecureElement & se, ECP256Certificate & cert, const String & deviceId, const String & notBefore, const String & notAfter, const String & serialNumber, const String & authorityKeyIdentifier, const String & signature, const SElementArduinoCloudSlot keySlot)
+{
+  byte serialNumberBytes[ECP256_CERT_SERIAL_NUMBER_LENGTH];
+  byte authorityKeyIdentifierBytes[ECP256_CERT_AUTHORITY_KEY_ID_LENGTH];
+  byte signatureBytes[ECP256_CERT_SIGNATURE_LENGTH];
+
+  if (!deviceId.length() || !notBefore.length() || !notAfter.length() || !serialNumber.length() || !authorityKeyIdentifier.length() || !signature.length() ) {
+    DEBUG_ERROR("SEACC::%s input params error.", __FUNCTION__);
+    return 0;
+  }
+
+  hexStringToBytes(serialNumber, serialNumberBytes, sizeof(serialNumberBytes));
+  hexStringToBytes(authorityKeyIdentifier, authorityKeyIdentifierBytes, sizeof(authorityKeyIdentifierBytes));
+  hexStringToBytes(signature, signatureBytes, sizeof(signatureBytes));
+
+  if (!cert.begin()) {
+    DEBUG_ERROR("SEACC::%s cert begin error", __FUNCTION__);
+    return -1;
+  }
+
+  cert.setSubjectCommonName(deviceId);
+  cert.setIssuerCountryName("US");
+  cert.setIssuerOrganizationName("Arduino LLC US");
+  cert.setIssuerOrganizationalUnitName("IT");
+  cert.setIssuerCommonName("Arduino");
+  cert.setSignature(signatureBytes, sizeof(signatureBytes));
+  cert.setAuthorityKeyId(authorityKeyIdentifierBytes, sizeof(authorityKeyIdentifierBytes));
+  cert.setSerialNumber(serialNumberBytes, sizeof(serialNumberBytes));
+  cert.setIssueYear(notBefore.substring(0,4).toInt());
+  cert.setIssueMonth(notBefore.substring(5,7).toInt());
+  cert.setIssueDay(notBefore.substring(8,10).toInt());
+  cert.setIssueHour(notBefore.substring(11,13).toInt());
+  cert.setExpireYears(notAfter.substring(0,4).toInt() - notBefore.substring(0,4).toInt());
+
+
+  if (!SElementCertificate::build(se, cert, static_cast<int>(keySlot))) {
+    DEBUG_ERROR("SEACC::%s cert build error", __FUNCTION__);
+    return -1;
+  }
+  return 1;
+}

src/utility/SElementArduinoCloudCertificate.h

@@ -28,6 +28,10 @@ class SElementArduinoCloudCertificate : public SElementCertificate
 
   static int write(SecureElement & se, ECP256Certificate & cert, const SElementArduinoCloudSlot certSlot);
   static int read(SecureElement & se, ECP256Certificate & cert, const SElementArduinoCloudSlot certSlot, const SElementArduinoCloudSlot keySlot = SElementArduinoCloudSlot::Key);
+  static int rebuild(SecureElement & se, ECP256Certificate & cert, const String & deviceId,
+                    const String & notBefore, const String & notAfter, const String & serialNumber,
+                    const String & authorityKeyIdentifier, const String & signature,
+                    const SElementArduinoCloudSlot keySlot = SElementArduinoCloudSlot::Key);
 
 };