This constant is the length of the largest string that can successfully be stored on Android.
Only if all the characters in the string are encoded in 1 byte in UTF-8 can a string actually be this big. Since characters in UTF-8 can take up to 4 bytes, if you do not know the contents of a string, the maximum length that is guaranteed to be successful is EncryptedStorage.COMPLEX_STRING_MAXIMUM_LENGTH, which is EncryptedStorage.SIMPLE_STRING_MAXIMUM_LENGTH/4. Note that this size restriction is present only on Android and not iOS.
<constant> SIMPLE_STRING_MAXIMUM_LENGTH