package org.jose4j.jwe;
import org.jose4j.jwa.AlgorithmInfo;
import org.jose4j.jwx.Headers;
import org.jose4j.keys.AesKey;
import org.jose4j.keys.KeyPersuasion;
import org.jose4j.lang.ByteUtil;
import org.jose4j.lang.JoseException;
/**
*
*/
public class AesGcmContentEncryptionAlgorithm extends AlgorithmInfo implements ContentEncryptionAlgorithm
{
private static final int IV_BYTE_LENGTH = 12;
private static final int TAG_BYTE_LENGTH = 16;
private ContentEncryptionKeyDescriptor contentEncryptionKeyDescriptor;
private SimpleAeadCipher simpleAeadCipher;
public AesGcmContentEncryptionAlgorithm(String alg, int keyBitLength)
{
setAlgorithmIdentifier(alg);
setJavaAlgorithm(SimpleAeadCipher.GCM_TRANSFORMATION_NAME);
setKeyPersuasion(KeyPersuasion.SYMMETRIC);
setKeyType(AesKey.ALGORITHM);
contentEncryptionKeyDescriptor = new ContentEncryptionKeyDescriptor(ByteUtil.byteLength(keyBitLength), AesKey.ALGORITHM);
simpleAeadCipher = new SimpleAeadCipher(getJavaAlgorithm(), TAG_BYTE_LENGTH);
}
public ContentEncryptionKeyDescriptor getContentEncryptionKeyDescriptor()
{
return contentEncryptionKeyDescriptor;
}
public ContentEncryptionParts encrypt(byte[] plaintext, byte[] aad, byte[] contentEncryptionKey, Headers headers, byte[] ivOverride)
throws JoseException
{
byte[] iv = InitializationVectorHelp.iv(IV_BYTE_LENGTH, ivOverride);
return encrypt(plaintext, aad, contentEncryptionKey, iv);
}
public ContentEncryptionParts encrypt(byte[] plaintext, byte[] aad, byte[] contentEncryptionKey, byte[] iv)
throws JoseException
{
AesKey cek = new AesKey(contentEncryptionKey);
SimpleAeadCipher.CipherOutput encrypted = simpleAeadCipher.encrypt(cek, iv, plaintext, aad);
return new ContentEncryptionParts(iv, encrypted.getCiphertext(), encrypted.getTag());
}
public byte[] decrypt(ContentEncryptionParts contentEncParts, byte[] aad, byte[] contentEncryptionKey, Headers headers)
throws JoseException
{
byte[] iv = contentEncParts.getIv();
AesKey cek = new AesKey(contentEncryptionKey);
byte[] ciphertext = contentEncParts.getCiphertext();
byte[] tag = contentEncParts.getAuthenticationTag();
return simpleAeadCipher.decrypt(cek, iv, ciphertext, tag, aad);
}
@Override
public boolean isAvailable()
{
int keyByteLength = getContentEncryptionKeyDescriptor().getContentEncryptionKeyByteLength();
return simpleAeadCipher.isAvailable(log, keyByteLength, IV_BYTE_LENGTH, getAlgorithmIdentifier());
}
public static class Aes256Gcm extends AesGcmContentEncryptionAlgorithm
{
public Aes256Gcm()
{
super(ContentEncryptionAlgorithmIdentifiers.AES_256_GCM, 256);
}
}
public static class Aes192Gcm extends AesGcmContentEncryptionAlgorithm
{
public Aes192Gcm()
{
super(ContentEncryptionAlgorithmIdentifiers.AES_192_GCM, 192);
}
}
public static class Aes128Gcm extends AesGcmContentEncryptionAlgorithm
{
public Aes128Gcm()
{
super(ContentEncryptionAlgorithmIdentifiers.AES_128_GCM, 128);
}
}
}