Verify APK signature

README.md

Do I have the correct certificate to sign my APK?

Use keytool Keytool is part of Java, so make sure your PATH has Java installation dir in it.

Get APK Certificate Signature

First, unzip the APK and extract the file /META-INF/ANDROID_.RSA (this file may also be CERT.RSA or something.RSA, but there should only be one .RSA file).

Then, run:

keytool -printcert -file ANDROID_.RSA

You will get the certificate fingerprint (MD5, SHA1, SHA256).

MD5:  B3:4F:BE:07:AA:78:24:DC:CA:92:36:FF:AE:8C:17:DB
SHA1: 16:59:E7:E3:0C:AA:7A:0D:F2:0D:05:20:12:A8:85:0B:32:C5:4F:68
Signature algorithm name: SHA1withRSA

Get certificate signature

Use keytool to get your certificate signature and check against the apk certificate signature

keytool -list -keystore path/to/my-signing-key.keystore

You will get a list of aliases and their certificate fingerprint:

android_key, Jan 23, 2010, PrivateKeyEntry,
Certificate fingerprint (MD5): B3:4F:BE:07:AA:78:24:DC:CA:92:36:FF:AE:8C:17:DB

If your certificate signature is the same as your APK signature, you are ready to go!

Source: http://stackoverflow.com/questions/11331469/how-do-i-find-out-which-keystore-was-used-to-sign-an-app

You can do this right on a phone with the App Manager application.
In a Files long tap on the apk file and press / Options / Open With / App Manager: About. Then on the Signatures tab you'll find a list of all signatures and verification status.