Authentication is successfully validating that an entity you are communicating with is actually who they claim to be. The entity typically demonstrates who they are by showing they possess a secret that only they could know.

learn more… | top users | synonyms

2
votes
1answer
632 views

Hash or encryption function for challenge-response protocol?

Say I have an authentication protocol where the shared secret is never transmitted. The server passes a challenge to the client and the client calculates a response using an algorithm where the ...
5
votes
1answer
855 views

What is the proper way to use a client nonce?

I've implemented an API for one of my clients, it relies on nonces and a shared secret. The structure: Client's Site (CS) requests nonce from My App (MA), posting their username MA verifies the ...
6
votes
1answer
1k views

How can I encrypt + authenticate short strings into similar short ciphertexts?

I wish to manipulate short ASCII strings (namely unpredictable domain names) into a form which cryptographically assures authenticity and confidentiality, for use in the local part of email addresses. ...
2
votes
1answer
158 views

Signature scheme with two private keys, neither derivable from the other

Is there any scheme, ideally one widely used or at least widely available, where you can treat both the signing and verifying keys as secret? Basically, the functionality I'm looking for is this: ...
4
votes
1answer
840 views

Need an introduction to SPKI (or “SPKI for dummies”)

I am familiar with concepts such as the following: PKI and CAs ID based cryptography Certificateless cryptography PGP web of trust more or less anything in basic Crypto that is taught in a college ...
6
votes
3answers
2k views

SHA1 usage for passwords, alternatives and advantages?

My application can authenticate via openid and oauth (facebook, twitter, etc) and also with its own authentication system. I previously switched hashing from MD5 to SHA1 and during migration I had to ...
2
votes
1answer
140 views

How to collect, process, and transmit data securely?

In my question "Authenticating data generated by a particular build of an open source program", Dave Cary requested that I post a question stating my real problem on a high level rather than the ...
8
votes
2answers
975 views

How should I store passwords that need to be available in plain text?

Suppose I need to store login information for a third-party website for a few users, how would I go about doing it? Since I am logging into a third party website, I need the password in plain-text, ...