OAEP (Optimal Asymmetric Encryption Padding)
is a method, developed by M.Bellare and P. Rogaway, for securely padding public-key encrypted data.
OFB (Output Feedback)
See Block cipher
OpenSSL is the open source project that implements SSL (V2/V3) and TLS. OpenSSL is sometimes also used just for its excellent cryptographic libray. It is probably the most known security open source project. For more details, see http://www.openssl.org
OPIMA (Open Platform Initiative for Multimedia Access)
is a framework that should allow to acquire, supply, process and consume multimedia services in accordance with the rights associated to these services. The current version of the specifications is 1.1 It is not well introduced in the community. The address of the OPIMA web site is http://www.cselt.it/opima/
is the perfect encryption scheme. It is a streamcipher that XORs the message with the key. The size of the key is equal to the size of the message. The key is a true random number. Thus the ciphertext is a perfect random number. Both emitter and receiver have agreed in advance to the used keys. A one-time pad key is used only once. The difficulty is in the key delivery system (physical delivery)
It is only in use for the ultra confidential low bandwidth channel.
One way Function
is a mathematical function that is significantly easier to perform in one direction than in the opposite direction. Trap door one way function is a one way function where the inverse direction is easy, given a piece of information.