org.bouncycastle.bcpg.FingerprintUtil Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of bcpg-lts8on Show documentation
The Bouncy Castle Java APIs for the OpenPGP Protocol. The APIs are designed primarily to be used in conjunction with the BC LTS provider but may also be used with other providers providing cryptographic services.
The newest version!
package org.bouncycastle.bcpg;

import org.bouncycastle.util.Pack;
import org.bouncycastle.util.encoders.Hex;

public class FingerprintUtil
{

    /**
     * Derive a key-id from the given key fingerprint.
     * This method can derive key-ids from v4, v5 (LibrePGP) and v6 keys.
     * For keys with other versions (2,3) it will return 0.
     *
     * @param keyVersion version of the key
     * @param fingerprint fingerprint of the key
     * @return derived key-id
     */
    public static long keyIdFromFingerprint(int keyVersion, byte[] fingerprint)
    {
        switch (keyVersion)
        {
            case PublicKeyPacket.VERSION_4:
                return keyIdFromV4Fingerprint(fingerprint);
            case PublicKeyPacket.LIBREPGP_5:
                return keyIdFromLibrePgpFingerprint(fingerprint);
            case PublicKeyPacket.VERSION_6:
                return keyIdFromV6Fingerprint(fingerprint);
            default:
                return 0;
        }
    }

    /**
     * Derive a 64 bit key-id from a version 6 OpenPGP fingerprint.
     * For v6 keys, the key-id corresponds to the left-most 8 octets of the fingerprint.
     *
     * @param v6Fingerprint 32 byte fingerprint
     * @return key-id
     */
    public static long keyIdFromV6Fingerprint(byte[] v6Fingerprint)
    {
        return longFromLeftMostBytes(v6Fingerprint);
    }

    /**
     * Derive a 64 bit key-id from a version 5 LibrePGP fingerprint.
     * For such keys, the key-id corresponds to the left-most 8 octets of the fingerprint.
     *
     * @param v5Fingerprint 32 byte fingerprint
     * @return key-id
     */
    public static long keyIdFromLibrePgpFingerprint(byte[] v5Fingerprint)
    {
        return longFromLeftMostBytes(v5Fingerprint);
    }

    /**
     * Derive a 64 bit key-id from a version 4 OpenPGP fingerprint.
     * For v4 keys, the key-id corresponds to the right-most 8 octets of the fingerprint.
     *
     * @param v4Fingerprint 20 byte fingerprint
     * @return key-id
     */
    public static long keyIdFromV4Fingerprint(byte[] v4Fingerprint)
    {
        return longFromRightMostBytes(v4Fingerprint);
    }

    /**
     * Convert the left-most 8 bytes from the given array to a long.
     *
     * @param bytes bytes
     * @return long
     */
    public static long longFromLeftMostBytes(byte[] bytes)
    {
        return readKeyID(bytes);
    }

    /**
     * Convert the right-most 8 bytes from the given array to a long.
     *
     * @param bytes bytes
     * @return long
     */
    public static long longFromRightMostBytes(byte[] bytes)
    {
        return readKeyID(bytes, bytes.length - 8);
    }

    /**
     * Read a key-ID from the first 8 octets of the given byte array.
     * @param bytes byte array
     * @return key-ID
     */
    public static long readKeyID(byte[] bytes)
    {
        return readKeyID(bytes, 0);
    }

    /**
     * Read a key-ID from 8 octets of the given byte array starting at offset.
     * @param bytes byte array
     * @param offset offset
     * @return key-ID
     */
    public static long readKeyID(byte[] bytes, int offset)
    {
        if (bytes.length < 8)
        {
            throw new IllegalArgumentException("Byte array MUST contain at least 8 bytes");
        }
        return Pack.bigEndianToLong(bytes, offset);
    }

    /**
     * Write the key-ID encoded as 8 octets to the given byte array, starting at index offset.
     * @param keyID keyID
     * @param bytes byte array
     * @param offset starting offset
     */
    public static void writeKeyID(long keyID, byte[] bytes, int offset)
    {
        if (bytes.length - offset < 8)
        {
            throw new IllegalArgumentException("Not enough space to write key-ID to byte array.");
        }
        Pack.longToBigEndian(keyID, bytes, offset);
    }

    /**
     * Write the key-ID to the first 8 octets of the given byte array.
     * @param keyID keyID
     * @param bytes byte array
     */
    public static void writeKeyID(long keyID, byte[] bytes)
    {
        writeKeyID(keyID, bytes, 0);
    }

    public static String prettifyFingerprint(byte[] fingerprint)
    {
        // -DM Hex.toHexString
        char[] hex = Hex.toHexString(fingerprint).toUpperCase().toCharArray();
        StringBuilder sb = new StringBuilder();
        switch (hex.length)
        {
            case 32:
                // v3 keys
                for (int i = 0; i < 4; i++)
                {
                    sb.append(hex, i * 4, 4).append(' ');
                }
                sb.append(' ');
                for (int i = 4; i < 7; i++)
                {
                    sb.append(hex, i * 4, 4).append(' ');
                }
                sb.append(hex, 28, 4);
                return sb.toString();
            case 40:
                // v4 keys
                for (int i = 0; i <= 4; i++)
                {
                    sb.append(hex, i * 4, 4).append(' ');
                }
                sb.append(' ');
                for (int i = 5; i <= 8; i++)
                { 
                    sb.append(hex, i * 4, 4).append(' ');
                }
                sb.append(hex, 36, 4);
                return sb.toString();
            case 64:
                // v5, v6 keys
                for (int i = 0; i < 4; i++)
                {
                    sb.append(hex, i * 8, 8).append(' ');
                }
                sb.append(' ');
                for (int i = 4; i < 7; i++)
                {
                    sb.append(hex, i * 8, 8).append(' ');
                }
                sb.append(hex, 56, 8);
                return sb.toString();
            default:
                return new String(hex);
        }
    }
}