Hello!

I've a question regarding distributed transactions. Let's assume I have 3 transaction programs:

Transaction A

1. begin
2. a=read(A)
3. b=read(B)
4. c=a+b
5. write(C,c)
6. commit

Transaction B

1. begin
2. a=read(A)
3. a=a+1
4. write(A,a)
5. commit

Transaction C

1. begin
2. c=read(C)
3. c=c*2
4. write(A,c)
5. commit

So there are 5 pairs of critical operations: C2-A5, A2-B4, B4-C4, B2-C4, A2-C4.

I should ensure integrity and confidentiality, do you have any idea of how to achieve it?

Thank you in advance!