It's a common mistake, when we're going to generate Signed APK in Android Studio. So in Keystore file you can't use any special character or symbol such as (, \ + - * / < > ; ' ") otherwise, you get java.io.IoException.
See a Demo, how can you fill-up your Keystore file:
Password: anything without special character or symbol
Alias: Key0 (up to you)
Validity (years): 25 (up to you)
First and last Name: Your proper Name but don't use special character in your name like $unny @dam
Organizational Unit: Your organization Name
Organization: Your organization Name
City or Locality: Your City Name
State or Province: Your State or Province Name
Country Code (XX): Use your country code, if you don't know then search Google.
Then click OK