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Retain RSA public exponent length when setting key attributes in putKey operation

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Similar to the previous commit, openpgp applet implementations differ in
regards to the public exponent length. As of this writing:
- The SmartPGP applet requires an 11 bit public exponent size
- The Gnuk token requires a 32 bit public exponent size

For this reason, we simply set the public exponent size to the one
previously set in the key attribute info. With this commit, the only
variable that can actually change for an RSA key is its modulus size.
This commit is contained in:
Vincent Breitmoser 2017-10-30 22:57:13 +01:00
parent 778fb8e94a
commit a51d0555e1
1 changed files with 20 additions and 16 deletions
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36
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenUtils.java
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@ -22,6 +22,7 @@ import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.encoders.Hex;
import org.sufficientlysecure.keychain.pgp.CanonicalizedSecretKey;
import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
import org.sufficientlysecure.keychain.securitytoken.RSAKeyFormat.RSAAlgorithmFormat;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
@ -33,24 +34,12 @@ import java.security.interfaces.RSAPrivateCrtKey;
class SecurityTokenUtils {
static byte[] attributesFromSecretKey(KeyType slot, CanonicalizedSecretKey secretKey, KeyFormat formatForKeyType)
throws IOException, PgpGeneralException {
throws IOException {
if (secretKey.isRSA()) {
final int mModulusLength = secretKey.getBitStrength();
final int mExponentLength = secretKey.getSecurityTokenRSASecretKey().getPublicExponent().bitLength();
final byte[] attrs = new byte[6];
int i = 0;
attrs[i++] = (byte) 0x01;
attrs[i++] = (byte) ((mModulusLength >> 8) & 0xff);
attrs[i++] = (byte) (mModulusLength & 0xff);
attrs[i++] = (byte) ((mExponentLength >> 8) & 0xff);
attrs[i++] = (byte) (mExponentLength & 0xff);
attrs[i] = ((RSAKeyFormat) formatForKeyType).getAlgorithmFormat().getValue();
return attrs;
return attributesForRsaKey(secretKey.getBitStrength(), (RSAKeyFormat) formatForKeyType);
} else if (secretKey.isEC()) {
final byte[] oid = new ASN1ObjectIdentifier(secretKey.getCurveOid()).getEncoded();
final byte[] attrs = new byte[1 + (oid.length - 2) + 1];
byte[] oid = new ASN1ObjectIdentifier(secretKey.getCurveOid()).getEncoded();
byte[] attrs = new byte[1 + (oid.length - 2) + 1];
if (slot.equals(KeyType.SIGN))
attrs[0] = ECKeyFormat.ECAlgorithmFormat.ECDSA_WITH_PUBKEY.getValue();
@ -68,6 +57,21 @@ class SecurityTokenUtils {
}
}
private static byte[] attributesForRsaKey(int modulusLength, RSAKeyFormat formatForKeyType) {
RSAAlgorithmFormat algorithmFormat = formatForKeyType.getAlgorithmFormat();
int exponentLength = formatForKeyType.getExponentLength();
int i = 0;
byte[] attrs = new byte[6];
attrs[i++] = (byte) 0x01;
attrs[i++] = (byte) ((modulusLength >> 8) & 0xff);
attrs[i++] = (byte) (modulusLength & 0xff);
attrs[i++] = (byte) ((exponentLength >> 8) & 0xff);
attrs[i++] = (byte) (exponentLength & 0xff);
attrs[i] = algorithmFormat.getValue();
return attrs;
}
static byte[] createRSAPrivKeyTemplate(RSAPrivateCrtKey secretKey, KeyType slot,
RSAKeyFormat format) throws IOException {