- #1
brajesh
- 62
- 15
- TL;DR Summary
- Understanding the RSA mathematics
Please help me understand the RSA encryption.
I understand part of it, then I don't understand.
Definitions:
M=plain text message
C=encrypted message
N=public key
E=encoding key
D=decoding key
P,Q are prime factors on N
I get that
P x Q = N (where P and Q are primes).
I get that
Φ(N) = (P-1) x (Q-1)
I get that
MEmodN = C
I get that
CDmodN = M
But after this I don't understand the relevance of this equation to solve D and E
D x E mod Φ(N) = 1
Seems to be some step or something obvious I'm missing?
I understand part of it, then I don't understand.
Definitions:
M=plain text message
C=encrypted message
N=public key
E=encoding key
D=decoding key
P,Q are prime factors on N
I get that
P x Q = N (where P and Q are primes).
I get that
Φ(N) = (P-1) x (Q-1)
I get that
MEmodN = C
I get that
CDmodN = M
But after this I don't understand the relevance of this equation to solve D and E
D x E mod Φ(N) = 1
Seems to be some step or something obvious I'm missing?