Cryptography

Cryptography is often synonymous with security encryption.

Cryptography is also referred as encryption, where encryption is the process of converting readable (text) information into unintelligible format for transmitting in a secure way.

For a complete seminar on Cryptography, you may consider the following points:
Benaloh crypto system
Blum Blum Shub generator
Diffie-Hellman key exchange
Goldwasser-Micali crypto system
Okamoto-Uchiyama crypto system
Paillier crypto system
Rabin crypto system
RSA crypto system

Also refer to the following
Kerberos
MD5
SHA -- SHA-0,SHA-1,SHA-2,SHA-3
CRC32

Suggested Reading on the related topic:
Cryonics cryptography
cryptography and Steganography
Elliptic curve cryptography (ECC)
Quantum Cryptography

External References
http://en.wikipedia.org/wiki/Cryptography
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1588831
http://cryptography.org/
http://www.cryptographyworld.com/