DES-encrypt the constant ASCII string “KGS!@#$%”, resulting in two 8-byte ciphertext values. The DES CipherMode should be set to ECB, and PaddingMode should be set to NONE. These two ciphertext values are concatenated to form a 16-byte value, which is the LM hash. Security weaknesses LAN Manager authentication uses a particularly weak method of hashing a user's password known as the LM hash algorithm, stemming from the mid 1980s when viruses transmitted by floppy disks were the major concern. Although it is based on DES, a well-studied block cipher, the LM hash has several weaknesses in its design. This makes such hashes crackable in a matter of seconds using rainbow tables, or in a few minutes using brute force. Starting with Windows NT, it was replaced by NTLM, which is still vulnerable to rainbow tables, and brute force attacks unless long, unpredictable passwords are used, see password cracking. NTLM is used for logon with local accounts except on domain controllers since Windows Vista and later versions no longer maintain the LM hash by default. Kerberos is used in Active Directory Environments. The major weaknesses of LAN Manager authentication protocol are: Password length is limited to a maximum of 14 characters chosen from the 95 ASCII printable characters. Passwords are not case sensitive. All passwords are converted into uppercase before generating the hash value. Hence LM hash treats PassWord, password, PaSsWoRd, PASSword and other similar combinations same as PASSWORD. This practice effectively reduces the LM hash key space to 69 characters. A 14-character password is broken into 7+7 characters and the hash is calculated for each half separately. This way of calculating the hash makes it dramatically easier to crack, as the attacker only needs to brute-force 7 characters twice instead of the full 14 characters. This makes the effective strength of a 14-character password equal to only , or twice that of a 7-character password, which is 3.7 trillion times less complex than the theoretical strength of a 14-character single-case password. As of 2020, a computer equipped with a high-end graphics processor (GPUs) can compute 40 billion LM-hashes per second. At that rate, all 7-character passwords from the 95-character set can be tested and broken in half an hour; all 7-character alphanumeric passwords can be tested and broken in 2 seconds. If the password is 7 characters or less, then the second half of hash will always produce same constant