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MattJackson
c8eb42b490
is_unit_encrypted read the TP_extra copy-control bits (byte 0), which are a copy-permission flag, not an encryption flag. On discs whose sampled units are clear navigation packets (PAT/PMT) those bits can be set while the unit is not scrambled, so a correct Unit Key was used to 'decrypt' already-plaintext data, produced garbage, and the key was wrongly treated as failing. Read the actual flag instead: the TS transport_scrambling_control bits (top two of TS-header byte 3 = byte 7 of the aligned unit, inside the clear seed). AACS encrypts whole aligned units, so this one packet's TSC reflects the unit. decrypt_unit now clears the TSC bits of every packet on the way out so the result is valid unscrambled TS. Tests updated to the TSC flag.