Public-key Cryptography: Theory and Practice

Chapter Summary

All the material studied in earlier chapters culminates in this relatively short chapter which describes some popular cryptographic algorithms. We address most of the problems relevant in cryptography, namely, encryption, key agreement, digital signatures and entity authentication. Against each algorithm we mention the (provable or alleged) source of security of the algorithm.

Encryption algorithms are treated first. We start with the seemingly most popular RSA algorithm. This algorithm derives its security from the RSA key inversion problem and the RSA problem. The key inversion problem is probabilistic polynomial-time equivalent to the integer factorization problem. The intractability of the RSA problem is unknown. At present ...