There is an interesting bug in the Android OS posted late last year.
The Bug
The bug poses a vulnerability in the way a password is translated into a key using the PBKDF2 function. It looks like the implementation ignored unicode by only using half of the data for each character while still accepting the full 16 bits per unicode character. Normally the last part, or least significant 8 bits of unicode roughly translates to ASCII in first unicode character set (0000 – 00FF).
Android OS filters out any unicode passwords at the input stage in the Screen Lock settings UI, so in theory it should not be possible to set a Screen Lock password with any unicode characters. Only the default ASCII characters from the first set are allowed.
How does this affect me?
read more........https://viaforensics.com/android-forensics/android-encryption-pbkdf2.html