package com.google.bitcoin.bouncycastle.asn1.x509; import com.google.bitcoin.bouncycastle.asn1.ASN1InputStream; import com.google.bitcoin.bouncycastle.asn1.DERObject; import com.google.bitcoin.bouncycastle.asn1.DERObjectIdentifier; import com.google.bitcoin.bouncycastle.asn1.DERPrintableString; import com.google.bitcoin.bouncycastle.util.Strings; import java.io.IOException; /** * It turns out that the number of standard ways the fields in a DN should be * encoded into their ASN.1 counterparts is rapidly approaching the * number of machines on the internet. By default the X509Name class * will produce UTF8Strings in line with the current recommendations (RFC 3280). * <p> * An example of an encoder look like below: * <pre> * public class X509DirEntryConverter * extends X509NameEntryConverter * { * public DERObject getConvertedValue( * DERObjectIdentifier oid, * String value) * { * if (str.length() != 0 && str.charAt(0) == '#') * { * return convertHexEncoded(str, 1); * } * if (oid.equals(EmailAddress)) * { * return new DERIA5String(str); * } * else if (canBePrintable(str)) * { * return new DERPrintableString(str); * } * else if (canBeUTF8(str)) * { * return new DERUTF8String(str); * } * else * { * return new DERBMPString(str); * } * } * } */ public abstract class X509NameEntryConverter { /** * Convert an inline encoded hex string rendition of an ASN.1 * object back into its corresponding ASN.1 object. * * @param str the hex encoded object * @param off the index at which the encoding starts * @return the decoded object */ protected DERObject convertHexEncoded( String str, int off) throws IOException { str = Strings.toLowerCase(str); byte[] data = new byte[(str.length() - off) / 2]; for (int index = 0; index != data.length; index++) { char left = str.charAt((index * 2) + off); char right = str.charAt((index * 2) + off + 1); if (left < 'a') { data[index] = (byte)((left - '0') << 4); } else { data[index] = (byte)((left - 'a' + 10) << 4); } if (right < 'a') { data[index] |= (byte)(right - '0'); } else { data[index] |= (byte)(right - 'a' + 10); } } ASN1InputStream aIn = new ASN1InputStream(data); return aIn.readObject(); } /** * return true if the passed in String can be represented without * loss as a PrintableString, false otherwise. */ protected boolean canBePrintable( String str) { return DERPrintableString.isPrintableString(str); } /** * Convert the passed in String value into the appropriate ASN.1 * encoded object. * * @param oid the oid associated with the value in the DN. * @param value the value of the particular DN component. * @return the ASN.1 equivalent for the value. */ public abstract DERObject getConvertedValue(DERObjectIdentifier oid, String value); }