How many bits does SYSKEY use for encryption?

32 bits is far too short for SYSKEY's encryption and does not correspond to the RC4 key length used by the SAM database protection mechanism.

64 bits is associated with older DES symmetric encryption, not the RC4 algorithm that SYSKEY employs.

512 bits is typical of asymmetric cryptography such as older RSA key sizes, not the symmetric RC4 stream cipher used by SYSKEY.

SYSKEY (SAM Lock Tool) uses a 128-bit RC4 encryption key to encrypt the Security Account Manager (SAM) database on Windows systems. This specific 128-bit key length is hardcoded into the SYSKEY implementation and applies to all three of its storage modes - stored in the registry, on a floppy disk, or derived from a passphrase.