crash at startup, cannot launch the application anymore

#### describe the bug
the application does not launch anymore. it crashes at startup. it was working fine a few days ago. it suddenly stopped working (without having done an update or anything else). restarted the device, same behavior. updated to the latest application version, same behavior. emptied application cache, same behavior.

deleting the application data and re-logging in fixed the issue.

#### to reproduce
steps to reproduce the behavior:
1. open the application

#### expected behavior
the application should launch.

#### smartphone (please complete the following information):
* device: motorola moto e 4g (2nd gen, 2015)
* os: cyanogenmod 12.1 (android 5.1.1)

#### additional context
* app version and store: 1.1.3, google play store
* homeserver: own, synapse 1.30.0

#### crash log
```
F/libc ( 5422): /usr/local/google/buildbot/src/android/ndk-release-r21/external/libcxx/../../external/libcxxabi/src/abort_message.cpp:72: abort_message: assertion "terminating with uncaught exception of type realm::util::DecryptionFailed: Decryption failed
F/libc ( 5422): Exception backtrace:
F/libc ( 5422): " failed
F/libc ( 5422): Fatal signal 6 (SIGABRT), code -6 in tid 5458 (DefaultDispatch)
I/DEBUG ( 303): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG ( 303): Build fingerprint: 'motorola/surnia_reteu/surnia_umts:5.0.2/LXI22.50-24.1/2:user/release-keys'
I/DEBUG ( 303): Revision: '33536'
I/DEBUG ( 303): ABI: 'arm'
I/DEBUG ( 303): pid: 5422, tid: 5458, name: DefaultDispatch >>> im.vector.app <<<
I/DEBUG ( 303): signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------
I/DEBUG ( 303): Abort message: '/usr/local/google/buildbot/src/android/ndk-release-r21/external/libcxx/../../external/libcxxabi/src/abort_message.cpp:72: abort_message: assertion "terminating with uncaught exception of type realm::util::DecryptionFailed: Decryption failed
I/DEBUG ( 303): Exception backtrace:
I/DEBUG ( 303): " failed'
I/DEBUG ( 303): r0 00000000 r1 00001552 r2 00000006 r3 00000000
I/DEBUG ( 303): r4 a1d17db8 r5 00000006 r6 0000000b r7 0000010c
I/DEBUG ( 303): r8 34567890 r9 00420160 sl b6e8ce04 fp 73bdffd8
I/DEBUG ( 303): ip 00001552 sp a1d171e0 lr b6e37791 pc b6e5a634 cpsr 600e0010
I/DEBUG ( 303):
I/DEBUG ( 303): backtrace:
I/DEBUG ( 303): #00 pc 00037634 /system/lib/libc.so (tgkill+12)
I/DEBUG ( 303): #01 pc 0001478d /system/lib/libc.so (pthread_kill+52)
I/DEBUG ( 303): #02 pc 000154ef /system/lib/libc.so (raise+10)
I/DEBUG ( 303): #03 pc 00011b55 /system/lib/libc.so (__libc_android_abort+36)
I/DEBUG ( 303): #04 pc 000100dc /system/lib/libc.so (abort+4)
I/DEBUG ( 303): #05 pc 00012e79 /system/lib/libc.so (__libc_fatal+16)
I/DEBUG ( 303): #06 pc 00011bd9 /system/lib/libc.so (__assert2+20)
I/DEBUG ( 303): #07 pc 00358f43 /data/app/im.vector.app-1/lib/arm/librealm-jni.so
I/DEBUG ( 303): #08 pc 00359045 /data/app/im.vector.app-1/lib/arm/librealm-jni.so
I/DEBUG ( 303): #09 pc 003575f9 /data/app/im.vector.app-1/lib/arm/librealm-jni.so
I/DEBUG ( 303): #10 pc 003575a3 /data/app/im.vector.app-1/lib/arm/librealm-jni.so (std::terminate()+46)
I/DEBUG ( 303): #11 pc 000a49b1 /data/app/im.vector.app-1/lib/arm/librealm-jni.so
```