I got this query while distrohopping. On Linux I have to enter my password erveytime I boot to decrypt the disk. But on windows I never had to do it. The first time windows bitlocker asked for password was when I booted into windows after installed Linux. Why is it so?


Yes, that is infact the situation Bitlocker wants to protect you from. Correct. I mean we can argue that’s not the case you need it to protect against but if we’re looking at non-drive-retrieval situations, then you can just have a password at the BIOS-level, you don’t need to encrypt the actual drive. Might as well save yourself the little CPU usage for encrypting/decrypting.
Bitlocker is specifically for th idea that someone circumvents any on-boot password and just takes the drive out, reading your files off of it directly.
Like any security measure it is not to be applied in isolation.
Just a side note: these days there usually isn’t any overhead for having a drive encrypted, the CPU isn’t even involved. The drive itself will decrypt the data itself.
Again, let me emphasize: usually. There are exceptions.