Android build release with iroha library

Question

I I have problem with build release apk file on android.

buildTypes {
        release {
            debuggable false
            useProguard true
            minifyEnabled true
            shrinkResources false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.config
        }
        debug {
            signingConfig signingConfigs.config
        }
    }

• when I did: minifyEnabled true after building release apk: app-release.apk, the app crashed because of generateKeyPair.
• when I did: minifyEnabled false after building release apk: app-release.apk, the build is okay.

Why does the build crash when minifyEnabled is true?