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#1630 DMR FLC ARC4/EP Encryption Parameters #1631

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Aug 18, 2023
Merged

#1630 DMR FLC ARC4/EP Encryption Parameters #1631

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33 changes: 30 additions & 3 deletions src/main/java/io/github/dsheirer/module/decode/dmr/message/data/lc/LCMessageFactory.java
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Expand Up @@ -33,12 +33,13 @@
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.TerminatorData;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.UnitToUnitVoiceChannelUser;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.UnknownFullLCMessage;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.hytera.HyteraArc4EncryptionParameters;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.hytera.HyteraGroupVoiceChannelUser;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.hytera.HyteraTerminator;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.hytera.HyteraUnitToUnitVoiceChannelUser;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.motorola.CapacityPlusEncryptedVoiceChannelUser;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.motorola.CapacityPlusWideAreaVoiceChannelUser;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.motorola.MotorolaEncryptionParameters;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.motorola.MotorolaArc4EncryptionParameters;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.motorola.MotorolaGroupVoiceChannelUser;
import io.github.dsheirer.module.decode.dmr.message.data.lc.shorty.ActivityUpdateMessage;
import io.github.dsheirer.module.decode.dmr.message.data.lc.shorty.CapacityPlusRestChannel;
Expand Down Expand Up @@ -122,8 +123,34 @@ else if(message.size() == 96)
case FULL_CAPACITY_PLUS_WIDE_AREA_VOICE_CHANNEL_USER:
flc = new CapacityPlusWideAreaVoiceChannelUser(message, timestamp, timeslot);
break;
case FULL_CAPACITY_PLUS_ENCRYPTION_PARAMETERS:
flc = new MotorolaEncryptionParameters(message, timestamp, timeslot);
case FULL_ARC4_ENCRYPTION_PARAMETERS:
boolean isHytera = false;

//This is apparently now a DMR standard FLC opcode, even though it's using Motorola's vendor ID (0x10).
//As observed on a known Hytera system, it's not using the standard FLC RS-12/9/4 check, which fails.
//It's apparently using the CRC-CCITT with 0x9696 initial fill. Not sure if both Hytera and Motorola
// are using this FEC. But, by using only 16 bits for checksum versus the standad 24, they're able to
// include a full 24-bit group/radio ID in the message. For now we'll identify as either Motorola
//(using reed solomon) or Hytera (using crc-ccitt).
if(!valid)
{
int bitErrors = CRCDMR.correctCCITT80(message, 0, 80, 0x9696);

if(bitErrors < 2)
{
valid = true;
isHytera = true;
}
}

if(isHytera)
{
flc = new HyteraArc4EncryptionParameters(message, timestamp, timeslot);
}
else
{
flc = new MotorolaArc4EncryptionParameters(message, timestamp, timeslot);
}
break;
case FULL_HYTERA_GROUP_VOICE_CHANNEL_USER:
flc = new HyteraGroupVoiceChannelUser(message, timestamp, timeslot);
Expand Down
2 changes: 1 addition & 1 deletion src/main/java/io/github/dsheirer/module/decode/dmr/message/data/lc/LCOpcode.java
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Expand Up @@ -49,7 +49,7 @@ public enum LCOpcode
//Observed on Cap+ Multi-Site System during an encrypted voice call
FULL_CAPACITY_PLUS_ENCRYPTED_VOICE_CHANNEL_USER(Vendor.MOTOROLA_CAPACITY_PLUS, true, 32, "ENCRYPTED VOICE CHANNEL USER"),
//Observed on Cap+ Multi-Site System during an encrypted voice call
FULL_CAPACITY_PLUS_ENCRYPTION_PARAMETERS(Vendor.MOTOROLA_CAPACITY_PLUS, true, 33, "ENCRYPTION PARAMETERS"),
FULL_ARC4_ENCRYPTION_PARAMETERS(Vendor.MOTOROLA_CAPACITY_PLUS, true, 33, "ARC4/EP ENCRYPTION PARAMETERS"),
//Cap+ opcodes from https://forums.radioreference.com/threads/understanding-capacity-plus-trunking-some-more.452566/
//FLCO 0: Group Call Maintenance
//FLCO 3: Private Call Maintenance (TermLC)
Expand Down
117 changes: 117 additions & 0 deletions ...sheirer/module/decode/dmr/message/data/lc/full/hytera/HyteraArc4EncryptionParameters.java
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@@ -0,0 +1,117 @@
/*
* *****************************************************************************
* Copyright (C) 2014-2023 Dennis Sheirer
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>
* ****************************************************************************
*/

package io.github.dsheirer.module.decode.dmr.message.data.lc.full.hytera;

import io.github.dsheirer.bits.CorrectedBinaryMessage;
import io.github.dsheirer.identifier.Identifier;
import io.github.dsheirer.module.decode.dmr.identifier.DMRTalkgroup;
import io.github.dsheirer.module.decode.dmr.message.data.lc.full.FullLCMessage;
import java.util.ArrayList;
import java.util.List;

/**
* Hytera ARC4/EP Encryption Parameters
* <p>
* Note: observed as FLC payload for a PI_HEADER slot type.
* Note: observed on a Hytera system that was configured as IP Site Connect compatible.
*/
public class HyteraArc4EncryptionParameters extends FullLCMessage
{
private static final int[] KEY_ID = new int[]{16, 17, 18, 19, 20, 21, 22, 23};
private static final int[] INITIALIZATION_VECTOR = new int[]{24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55};
private static final int[] DESTINATION_GROUP = new int[]{56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,
71, 72, 73, 74, 75, 76, 77, 78, 79};
//Hytera version uses CRC-CCITT with 0x9696 initial fill, bits: 80-95

private DMRTalkgroup mTalkgroup;
private List<Identifier> mIdentifiers;

/**
* Constructor
* @param message bits
* @param timestamp for the message
* @param timeslot of the message
*/
public HyteraArc4EncryptionParameters(CorrectedBinaryMessage message, long timestamp, int timeslot)
{
super(message, timestamp, timeslot);
}

@Override
public String toString()
{
StringBuilder sb = new StringBuilder();

if(!isValid())
{
sb.append("[CRC-ERROR] ");
}

if(isEncrypted())
{
sb.append(" *ENCRYPTED*");
}

if(isReservedBitSet())
{
sb.append(" *RESERVED-BIT*");
}

sb.append("FLC HYTERA ARC4/EP ENCRYPTION PARAMETERS");
sb.append(" KEY:").append(getKeyId());
sb.append(" IV:").append(getInitializationVector());
sb.append(" TALKGROUP:").append(getTalkgroup());
sb.append(" MSG:").append(getMessage().toHexString());
return sb.toString();
}

public DMRTalkgroup getTalkgroup()
{
if(mTalkgroup == null)
{
mTalkgroup = new DMRTalkgroup(getMessage().getInt(DESTINATION_GROUP));
}

return mTalkgroup;
}

public int getKeyId()
{
return getMessage().getInt(KEY_ID);
}

public String getInitializationVector()
{
return getMessage().getHex(INITIALIZATION_VECTOR, 8);
}

@Override
public List<Identifier> getIdentifiers()
{
if(mIdentifiers == null)
{
mIdentifiers = new ArrayList<>();
mIdentifiers.add(getTalkgroup());
}

return mIdentifiers;
}
}
34 changes: 11 additions & 23 deletions ...otorola/MotorolaEncryptionParameters.java → ...ola/MotorolaArc4EncryptionParameters.java
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Expand Up @@ -27,29 +27,29 @@
import java.util.List;

/**
* Motorola Encryption Parameters
* Motorola ARC4/EP Encryption Parameters
* <p>
* Note: observed as FLC payload for a PI_HEADER slot type.
* Note: observed on a possible Hytera (clone) system that was configured as IP Site Connect compatible.
*/
public class MotorolaEncryptionParameters extends FullLCMessage
public class MotorolaArc4EncryptionParameters extends FullLCMessage
{
private static final int[] KEY_ID = new int[]{16, 17, 18, 19, 20, 21, 22, 23};
private static final int[] INITIALIZATION_VECTOR = new int[]{24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55};
private static final int[] ALGORITHM = new int[]{56, 57, 58, 59, 60, 61, 62, 63};
private static final int[] DESTINATION_GROUP = new int[]{64, 65, 66, 67, 68, 69, 70, 71};
//Reed Solomon FEC: 72-95
private static final int[] DESTINATION_GROUP = new int[]{56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71};
//Motorola Reed Solomon FEC bits: 72-95

private DMRTalkgroup mTalkgroup;
private List<Identifier> mIdentifiers;

/**
* Constructs an instance.
*
* @param message for the link control payload
* Constructor
* @param message bits
* @param timestamp for the message
* @param timeslot of the message
*/
public MotorolaEncryptionParameters(CorrectedBinaryMessage message, long timestamp, int timeslot)
public MotorolaArc4EncryptionParameters(CorrectedBinaryMessage message, long timestamp, int timeslot)
{
super(message, timestamp, timeslot);
}
Expand All @@ -74,9 +74,9 @@ public String toString()
sb.append(" *RESERVED-BIT*");
}

sb.append("FLC MOTOROLA ENCRYPTION PARAMETERS - ALGORITHM:").append(getAlgorithm());
sb.append("FLC MOTOROLA ARC4/EP ENCRYPTION PARAMETERS");
sb.append(" KEY:").append(getKeyId());
sb.append(" IV?:").append(getInitializationVector());
sb.append(" IV:").append(getInitializationVector());
sb.append(" TALKGROUP:").append(getTalkgroup());
sb.append(" MSG:").append(getMessage().toHexString());
return sb.toString();
Expand All @@ -97,18 +97,6 @@ public int getKeyId()
return getMessage().getInt(KEY_ID);
}

public String getAlgorithm()
{
int algorithm = getMessage().getInt(ALGORITHM);

if(algorithm == 0)
{
return "EP/ARC4";
}

return "UNK(" + algorithm + ")";
}

public String getInitializationVector()
{
return getMessage().getHex(INITIALIZATION_VECTOR, 8);
Expand Down
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