diff --git a/doc/Android_code_signing.adoc b/doc/Android_code_signing.adoc
new file mode 100644
index 0000000..a5774e3
--- /dev/null
+++ b/doc/Android_code_signing.adoc
@@ -0,0 +1,59 @@
+Load and use Android code signing certificate
+---------------------------------------------
+
+This is a step-by-step guide on how to load and use an android code signing
+key and certificate.
+
+Prerequisites
+-------------
+
+* a YubiKey with the PIV application
+* the yubico-piv-tool software
+* the OpenSC software
+* jarsigner and keytool from the JDK (openjdk 8 used here)
+
+Steps
+-----
+
+1. Import the key and cert, do a or b
+a. Import the key and cert (PEM format) in slot 9a:
+
+  $ yubico-piv-tool -s 9a -a import-key -i key.pem
+  $ yubico-piv-tool -s 9a -a import-certificate -i cert.pem
+
+b. Import the key and cert (PKCS12 format) in slot 9a:
+
+  $ yubico-piv-tool -s 9a -a import-key -a import-cert -i key.p12 -K PKCS12
+
+2. Create a java pkcs11 configuration file:
+
+  cat > /tmp/pkcs11_java.cfg
+  name = OpenSC-PKCS11
+  description = SunPKCS11 via OpenSC
+  library = /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so
+  slotListIndex = 1
+
+3. Check that keytool can see the key:
+
+  $ keytool -providerClass sun.security.pkcs11.SunPKCS11 -providerArg /tmp/pkcs11_java.cfg -keystore NONE -storetype PKCS11 -list
+  Enter keystore password:
+
+  Keystore type: PKCS11
+  Keystore provider: SunPKCS11-OpenSC-PKCS11
+
+  Your keystore contains 1 entry
+
+  Certificate for PIV Authentication, PrivateKeyEntry,
+  Certificate fingerprint (SHA1): 26:D7:CB:71:6D:42:3C:AB:58:69:E0:9D:F0:16:DF:84:7E:1C:5A:9A
++
+Password here is the PIN of the key (default 123456).
+
+4. Sign the apk with jarsigner:
+
+  $ jarsigner -providerClass sun.security.pkcs11.SunPKCS11 -providerArg /tmp/pkcs11_java.cfg -keystore NONE -storetype PKCS11 app.apk "Certificate for PIV Authentication"
+  Enter Passphrase for keystore: 
+  jar signed.
+
+5. Verify the signature with jarsigner:
+
+  $ jarsigner -verify app.apk