/// <summary>
/// Derive a new encrypt key from the given decrypt key value.
/// </summary>
///
/// <param name="keyBits"></param>
/// <returns>The new encrypt key (DER-encoded public key).</returns>
public static EncryptKey deriveEncryptKey(Blob keyBits)
{
// Decode the PKCS #8 private key. (We don't use RSAPrivateCrtKey because
// the Android library doesn't have an easy way to decode into it.)
DerNode parsedNode = net.named_data.jndn.encoding.der.DerNode.parse(keyBits.buf(), 0);
IList pkcs8Children = parsedNode.getChildren();
IList algorithmIdChildren = net.named_data.jndn.encoding.der.DerNode.getSequence(pkcs8Children, 1)
.getChildren();
String oidString = ((DerNode.DerOid)algorithmIdChildren[0])
.toVal().toString();
Blob rsaPrivateKeyDer = ((DerNode)pkcs8Children[2]).getPayload();
String RSA_ENCRYPTION_OID = "1.2.840.113549.1.1.1";
if (!oidString.equals(RSA_ENCRYPTION_OID))
{
throw new DerDecodingException(
"The PKCS #8 private key is not RSA_ENCRYPTION");
}
// Decode the PKCS #1 RSAPrivateKey.
parsedNode = net.named_data.jndn.encoding.der.DerNode.parse(rsaPrivateKeyDer.buf(), 0);
IList rsaPrivateKeyChildren = parsedNode.getChildren();
Blob modulus = ((DerNode)rsaPrivateKeyChildren[1]).getPayload();
Blob publicExponent = ((DerNode)rsaPrivateKeyChildren[2])
.getPayload();
System.SecurityPublicKey publicKey = keyFactory_
.generatePublic(new RSAPublicKeySpec(new Int64(modulus
.getImmutableArray()), new Int64(publicExponent
.getImmutableArray())));
return(new EncryptKey(new Blob(publicKey.getEncoded(), false)));
}
/// <summary>
/// Get the encoded public key for this private key.
/// </summary>
///
/// <returns>The public key encoding Blob.</returns>
/// <exception cref="TpmPrivateKey.Error">if no private key is loaded, or errorconverting to a public key.</exception>
public Blob derivePublicKey()
{
if (keyType_ == net.named_data.jndn.security.KeyType.EC)
{
throw new TpmPrivateKey.Error(
"TODO: derivePublicKey for EC is not implemented");
}
else if (keyType_ == net.named_data.jndn.security.KeyType.RSA)
{
// Decode the PKCS #1 RSAPrivateKey. (We don't use RSAPrivateCrtKey because
// the Android library doesn't have an easy way to decode into it.)
IList rsaPrivateKeyChildren;
try {
DerNode parsedNode = net.named_data.jndn.encoding.der.DerNode.parse(toPkcs1().buf(), 0);
rsaPrivateKeyChildren = parsedNode.getChildren();
} catch (DerDecodingException ex) {
throw new TpmPrivateKey.Error("Error parsing RSA PKCS #1 key: "
+ ex);
}
Blob modulus = ((DerNode)rsaPrivateKeyChildren[1])
.getPayload();
Blob publicExponent = ((DerNode)rsaPrivateKeyChildren[2])
.getPayload();
try {
System.SecurityPublicKey publicKey = System.KeyFactory.getInstance(
"RSA").generatePublic(
new RSAPublicKeySpec((modulus
.getImmutableArray()), (
publicExponent.getImmutableArray())));
return(new Blob(publicKey.getEncoded(), false));
} catch (Exception ex_0) {
throw new TpmPrivateKey.Error("Error making RSA public key: "
+ ex_0);
}
}
else
{
throw new TpmPrivateKey.Error(
"derivePublicKey: The private key is not loaded");
}
}
