Example usage for org.bouncycastle.util.encoders Hex encode

Introduction

In this page you can find the example usage for org.bouncycastle.util.encoders Hex encode.

Prototype

public static byte[] encode(byte[] data, int off, int length) 

Source Link

Document

encode the input data producing a Hex encoded byte array.

Usage

From source file:io.warp10.script.lora.LORAMIC.java

License:Apache License

@Override
public Object apply(WarpScriptStack stack) throws WarpScriptException {

    Object top = stack.pop();/*from  ww w  . j  a va 2s.co m*/

    if (!(top instanceof String)) {
        throw new WarpScriptException(getName() + " expects a 128 bits hex encoded key on top of the stack.");
    }

    String keystr = top.toString();

    if (keystr.length() != 32) {
        throw new WarpScriptException(getName() + " expects a 128 bits hex encoded key on top of the stack.");
    }

    top = stack.pop();

    if (!(top instanceof Long)) {
        throw new WarpScriptException(getName() + " expects a sequence counter below the key.");
    }

    int sequenceCounter = ((Number) top).intValue();

    top = stack.pop();

    if (!(top instanceof Long)) {
        throw new WarpScriptException(
                getName() + " expects a direction (0 uplink or 1 downlink) below the sequence counter.");
    }

    int dir = ((Number) top).intValue();

    if (0 != dir && 1 != dir) {
        throw new WarpScriptException(
                getName() + " expects a direction (0 uplink or 1 downlink) below the sequence counter.");
    }

    top = stack.pop();

    if (!(top instanceof Long)) {
        throw new WarpScriptException(getName() + " expects a device address below the direction.");
    }

    int addr = ((Number) top).intValue();

    String datastr = stack.pop().toString();

    if (0 != datastr.length() % 2) {
        throw new WarpScriptException(
                getName() + " expects a hex encoded data frame with an even length of hex digits.");
    }

    byte[] data = Hex.decode(datastr);

    //
    // Compute MIC block B0
    //

    byte[] MicBlockB0 = new byte[16];

    MicBlockB0[0] = 0x49;
    MicBlockB0[5] = (byte) (dir & 0x1);
    MicBlockB0[6] = (byte) (addr & 0xFF);
    MicBlockB0[7] = (byte) ((addr >> 8) & 0xFF);
    MicBlockB0[8] = (byte) ((addr >> 16) & 0xFF);
    MicBlockB0[9] = (byte) ((addr >> 24) & 0xFF);

    MicBlockB0[10] = (byte) ((sequenceCounter) & 0xFF);
    MicBlockB0[11] = (byte) ((sequenceCounter >> 8) & 0xFF);
    MicBlockB0[12] = (byte) ((sequenceCounter >> 16) & 0xFF);
    MicBlockB0[13] = (byte) ((sequenceCounter >> 24) & 0xFF);

    MicBlockB0[15] = (byte) (data.length & 0xFF);

    AESEngine aes = new AESEngine();
    CMac cmac = new CMac(aes);
    KeyParameter key = new KeyParameter(Hex.decode(keystr));
    cmac.init(key);
    cmac.update(MicBlockB0, 0, MicBlockB0.length);
    cmac.update(data, 0, data.length & 0xFF);

    byte[] mac = new byte[cmac.getMacSize()];
    cmac.doFinal(mac, 0);

    //    byte[] mic = new byte[4];
    //    mic[0] = mac[3];
    //    mic[1] = mac[2];
    //    mic[2] = mac[1];
    //    mic[3] = mac[0];

    stack.push(new String(Hex.encode(mac, 0, 4), Charsets.US_ASCII));

    return stack;
}

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