org.bouncycastle.crypto.parsers.ECIESPublicKeyParser.java Source code

Introduction

Here is the source code for org.bouncycastle.crypto.parsers.ECIESPublicKeyParser.java

Source

package org.bouncycastle.crypto.parsers;

import java.io.IOException;
import java.io.InputStream;

import org.bouncycastle.crypto.KeyParser;
import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.util.io.Streams;

public class ECIESPublicKeyParser implements KeyParser {
    private ECDomainParameters ecParams;

    public ECIESPublicKeyParser(ECDomainParameters ecParams) {
        this.ecParams = ecParams;
    }

    public AsymmetricKeyParameter readKey(InputStream stream) throws IOException {
        byte[] V;
        int first = stream.read();

        // Decode the public ephemeral key
        switch (first) {
        case 0x00: // infinity
            throw new IOException("Sender's public key invalid.");

        case 0x02: // compressed
        case 0x03: // Byte length calculated as in ECPoint.getEncoded();
            V = new byte[1 + (ecParams.getCurve().getFieldSize() + 7) / 8];
            break;

        case 0x04: // uncompressed or
        case 0x06: // hybrid
        case 0x07: // Byte length calculated as in ECPoint.getEncoded();
            V = new byte[1 + 2 * ((ecParams.getCurve().getFieldSize() + 7) / 8)];
            break;

        default:
            throw new IOException(
                    "Sender's public key has invalid point encoding 0x" + Integer.toString(first, 16));
        }

        V[0] = (byte) first;
        Streams.readFully(stream, V, 1, V.length - 1);

        return new ECPublicKeyParameters(ecParams.getCurve().decodePoint(V), ecParams);
    }
}