Encrypted security file used to store a set of cryptographic keys or certificates in the binary Java Key Store (JKS) format; requires a password to be opened.
JKS files are used for a variety of security purposes. They can be used to identify the author of an Android app during a build and when publishing to Android Market in Google Play or in SSL encryption. A JKS file contains sensitive data, so the file is encrypted and protected by a password to secure the file from unauthorized parties.
NOTE: .KEYSTORE files also use the JKS format for storing keys and certificates.