Understand encryption code?

Ok. I need to understand how the following code works. I then need to comment it to show what it does. If anyone could tell me how this works, it would be greatly appreciated.

// Inputs: register EAX = Encryption Key value, and ECX = the character to be encrypted.
// Outputs: register EAX = the encrypted value of the source character.

Encrypt11:
push edx
push ecx
ror al,1
ror al,1
ror al,1
mov edx,eax
pop eax
sub eax,0×02
xor eax,edx
rol al,1
rol al,1
rol al,1
pop edx
ret
}

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