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RSA. Rivest Shamir Adelman: Patented in 1983, expired in 2000 Based on difficulty of factorization Choose two large random prime numbers p and q, Compute n = p*q Compute φ (n) = (p-1)(q-1) Choose an integer e, such that e, is coprime to φ (n) -- e, is released as the public key
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RSA • Rivest Shamir Adelman: • Patented in 1983, expired in 2000 • Based on difficulty of factorization Choose two large random prime numbers p and q, Compute n = p*q Compute φ(n) = (p-1)(q-1) Choose an integer e, such that e, is coprime to φ(n) -- e, is released as the public key Compute d, to satisfy (d*e) mod φ(n) = 1 -- d, is kept as the private key
RSA • Encryption (of message m) (m)e mod n • Decryption (of cipher m’) (m’)e mod n • RSA property ((m)e)d mod n = m