| 1949 CE Claude Shannon publishes a paper on his Unicity Concept. The Unicity Concept measures the least amount of plaintext which can be uniquely deciphered from the corresponding ciphertext, given unbounded resouces by the attacker. |
| 1968 CE John Anthony Walker Jr., a Chief Warrant Officer and communications specialist for the U.S. Navy, begins seventeen years of espionage for the Soviet Union, copying keys and sending them to the Soviets. |
| 1968 CE James Ellis, Clifford Cocks and Malcolm Williamson are the original inventors of public key cryptography. Their work for GCHQ is kept secret until 1997. |
| 1971 CE Horst Feistel creates Lucifer at IBM's Thomas J. Watson Laboratory. Lucifer is an early block cipher, a direct precursor to DES. |
| 1973 CE David Bell and Len LaPadula create the Bell-LaPadula Security Policy Model, a model of computer security that describes access control rules. |
| 1976 CE Whitfield Diffie and Martin Hellman publish New Directions in Cryptography, introducing a new method of distributing cryptographic keys. |
| 1977 CE Ronald L. Rivest, Adi Shamir, and Leonard M. Adleman develop the RSA algorithm. |
| 1978 CE The RSA algorithm is published in the Communications of the ACM. |
| 1983 CE The U.S. Department of Defense publishes the Trusted Computer System Evaluation Criteria a.k.a. the Orange Book, a part of the Rainbow Series. |
| 1984 CE The ROT-13 shift cipher is introduced into USENET. More » |
| 1987 CE The Clark-Wilson Integrity Model is developed and used. |
| 1987 CE Ron Rivest develops RC4 a.k.a. ARCFOUR stream cipher. |
| 1988 CE Kerberos, the network authentication protocol, is developed at MIT |
| 1990 CE Charles H. Bennett, Gilles Brassard, et al publish their experimental results on Quantum Cryptography. |
| 1990 CE Xuejia Lai and James Massey publish A Proposal for a New Block Encryption Standard, a proposed International Data Encryption Algorithm (IDEA) to replace DES. |
| 1991 CE Phil Zimmermann publishes PGP (Pretty Good Privacy). |
| 1993 CE The Clipper Chip a.k.a. Escrowed Encryption Standard is announced. |
| 1993 CE Bruce Schneier develops Blowfish algorithm. |
| 1994 CE Ron Rivest develops RC5. |
| 1997 CE distributed.net, the first general-purpose distributed computing project, is founded. |
| 1998 CE The Digital Millennium Copyright Act (DMCA), which criminalizes copyright circumvention, becomes U.S. law. |
| 1998 CE Electronic Frontier Foundation uses Deep Crack to brute force DES. |
| 2000 CE RSA algorithm is released into the public domain. |
| 2004 CE MD5 hash is shown to be vulnerable to practical collision attack. |
| Present Day You are here. |