package com.google.crypto.tink.aead;
import com.google.crypto.tink.KeyTypeManager;
import com.google.crypto.tink.Registry;
import com.google.crypto.tink.proto.AesCtrKey;
import com.google.crypto.tink.proto.AesCtrKeyFormat;
import com.google.crypto.tink.proto.AesCtrParams;
import com.google.crypto.tink.proto.KeyData.KeyMaterialType;
import com.google.crypto.tink.subtle.AesCtrJceCipher;
import com.google.crypto.tink.subtle.IndCpaCipher;
import com.google.crypto.tink.subtle.Random;
import com.google.crypto.tink.subtle.Validators;
import com.google.protobuf.ByteString;
import com.google.protobuf.ExtensionRegistryLite;
import com.google.protobuf.InvalidProtocolBufferException;
import java.security.GeneralSecurityException;
public class AesCtrKeyManager extends KeyTypeManager<AesCtrKey> {
AesCtrKeyManager() {
super(
AesCtrKey.class,
new PrimitiveFactory<IndCpaCipher, AesCtrKey>(IndCpaCipher.class) {
@Override
public IndCpaCipher getPrimitive(AesCtrKey key) throws GeneralSecurityException {
return new AesCtrJceCipher(
key.getKeyValue().toByteArray(), key.getParams().getIvSize());
}
});
}
private static final int MIN_IV_SIZE_IN_BYTES = 12;
@Override
public String getKeyType() {
return "type.googleapis.com/google.crypto.tink.AesCtrKey";
}
@Override
public int getVersion() {
return 0;
}
@Override
public KeyMaterialType keyMaterialType() {
return KeyMaterialType.SYMMETRIC;
}
@Override
public void validateKey(AesCtrKey key) throws GeneralSecurityException {
Validators.validateVersion(key.getVersion(), getVersion());
Validators.validateAesKeySize(key.getKeyValue().size());
validateParams(key.getParams());
}
@Override
public AesCtrKey parseKey(ByteString byteString) throws InvalidProtocolBufferException {
return AesCtrKey.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry());
}
@Override
public KeyFactory<AesCtrKeyFormat, AesCtrKey> keyFactory() {
return new KeyFactory<AesCtrKeyFormat, AesCtrKey>(AesCtrKeyFormat.class) {
@Override
public void validateKeyFormat(AesCtrKeyFormat format) throws GeneralSecurityException {
Validators.validateAesKeySize(format.getKeySize());
validateParams(format.getParams());
}
@Override
public AesCtrKeyFormat parseKeyFormat(ByteString byteString)
throws InvalidProtocolBufferException {
return AesCtrKeyFormat.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry());
}
@Override
public AesCtrKey createKey(AesCtrKeyFormat format) throws GeneralSecurityException {
return AesCtrKey.newBuilder()
.setParams(format.getParams())
.setKeyValue(ByteString.copyFrom(Random.randBytes(format.getKeySize())))
.setVersion(getVersion())
.build();
}
};
}
private void validateParams(AesCtrParams params) throws GeneralSecurityException {
if (params.getIvSize() < MIN_IV_SIZE_IN_BYTES || params.getIvSize() > 16) {
throw new GeneralSecurityException("invalid IV size");
}
}
public static void register(boolean newKeyAllowed) throws GeneralSecurityException {
Registry.registerKeyManager(new AesCtrKeyManager(), newKeyAllowed);
}
}