Cryptosystem ME6 is a Windows program which uses a symmetric key encryption system to encrypt information in either a single file or in multiple files (at once) so that it cannot be read by those not knowing the key. Data is encrypted using a key which is from 16 to 64 characters long, and which can be either a phrase or a sequence of 64 random bytes (the software provides a way for you to generate such random keys). Without the key the encrypted data is unintelligible and the information cannot be read. The size, the type and the number of files which can be encrypted in a single operation is unlimited. You can encrypt a single file 'in place' (overwriting it with the ciphertext) or encrypt it to a different file. Multiple files can also be specified by using wildcards, e.g., '*.txt' to encrypt all files with 'txt' suffix. Files are compressed before encryption (which also makes cryptanalysis more difficult). There are various options which allow you to customize the operation of the program. For example, you can request the program to operate on files not only in a specified folder but also in all lower folders (this is useful for encrypting an entire project which has files in subfolders). There are several safeguards against the possibility of user error when encrypting or decrypting.