使用proguard缩小库jar，但保留指定的类

Question

我想缩小spongycastle核心jar，但保留几个类及其依赖项。我使用proguard，但我只使用指定的类

这是我的配置：

-injars       core-1.54.0.0.jar
-outjars      core-1.54.0.0-shrinked.jar
-libraryjars  /Users/abc/Library/Android/sdk/platforms/android-23/android.jar
-printmapping out.map

-dontpreverify
-dontobfuscate
-repackageclasses ''
-allowaccessmodification
-optimizations !code/simplification/arithmetic
-keepparameternames
-renamesourcefileattribute SourceFile
-keepattributes Exceptions,InnerClasses,Signature,Deprecated,
                SourceFile,LineNumberTable,*Annotation*,EnclosingMethod

-keep public class org.spongycastle.crypto.BlockCipher
-keep public class org.spongycastle.crypto.engines.AESFastEngine
-keep public class org.spongycastle.crypto.macs.CMac
-keep public class org.spongycastle.crypto.params.KeyParameter