This version of the libcrypt.so.1 library has entirely removed the functionality of the encrypt, encrypt_r, setkey, setkey_r, and fcrypt functions, while keeping fully binary compatibility with existing (third-party) applications possibly still using those funtions. If such an application attemps to call one of these functions, the corresponding function will indicate that it is not supported by the system in a POSIX-compliant way. For security reasons, the encrypt and encrypt_r functions will also overwrite their data-block argument with random bits. All existing binary executables linked against glibc's libcrypt should work unmodified with the provided version of the libcrypt.so.1 library in place.