Public Key Cryptography:

A public key cipher is one in which the key used for encryption is different from the one used for decryption. Although the keys are related, it is not possible to calculate the decryption key from only the encryption key in any reasonable amount of computation time. In most practical systems, the public key system is used for encoding a session key which is used with a symmetric system to encode the actual data. RSA is an example of a public key algorithm.

RC2:

A symmetric key block cipher, developed by RSA Data Security Inc, and now widely available.

RC4:

A symmetric key stream cipher, developed by RSA Data Security Inc, and now widely available.

RSA:

RSA is a public key cipher which can be used both for encrypting messages and making digital signatures The letters stand for the names of the inventors: Rivest, Shamir and Adleman. The company RSA Data Security Inc. takes its name from this algorithm, and has acquired the rights to the patents which cover it.

RSAREF:

RSAREF is an implementation of the RSA public key system, and associated utilities, produced by RSA Data Security Inc. It is licensed without fee for non-commercial use.

Safe Passage:

A recently announced solution to the problem that "export" versions of the Microsoft & Netscape browsers are only capable of using 40-bit keys, and so cannot negotiate full strength sessions when connecting to servers capable of strong encryption. c2.net have made this functionality available as an http proxy.

Self-signed Certificate:

It is possible for the owner of a certificate to sign it themselves instead of having a recognised certification authority do so. This is unlikely to be trusted by anyone wishing to use the certificate as proof of ownership of the corresponding public key. However, a signature by the owner is still useful, especially when the owner is a certification authority which must be trusted for independent reasons, as it restricts the possibilities for malicious or accidental changes to the details contained in the certificate.

Secret Key:

Confusingly sometimes used to mean the private key of a public key system, and also sometimes used (in contrast to "public key") to refer to a symmetric key system.