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How is the HMAC key used in encryption?
1 Answer 1. An HMAC key is a symmetric key, i.e. a bunch of bytes. The “symmetry” relates to the following important fact: the very same key is used both to produce a HMAC value over some message, and to verify the HMAC value over the message.
How is the HMAC key exchanged with a PKI?
The complete picture is that PKI is used to distribute public keys, and these public keys are then used with asymmetric cryptography to dynamically create a shared secret, and that shared secret is then used with symmetric algorithms such as HMAC. So you do not distribute HMAC keys directly with a PKI; there is one intermediate layer.
Is the HMAC key the same as the signature?
The “symmetry” relates to the following important fact: the very same key is used both to produce a HMAC value over some message, and to verify the HMAC value over the message. In that sense, HMAC is not a digital signature algorithm (but some people are nonetheless talking of “signatures” about HMAC, which is both wrong and confusing).
How is the HMAC key exchanged in SSL / TLS?
In SSL/TLS, the usual MAC algorithm is HMAC. The complete picture is that PKI is used to distribute public keys, and these public keys are then used with asymmetric cryptography to dynamically create a shared secret, and that shared secret is then used with symmetric algorithms such as HMAC.
How to calculate HMAC and derive a password?
As more complicated KDF function, you can derive a password by calculating HMAC (salt, msg, SHA256) using some random value called “salt”, which is stored along with the derived key and used later to derive the same key again from the password.
Is the HMAC key symmetric or non symmetric?
An HMAC key is a symmetric key, i.e. a bunch of bytes. The “symmetry” relates to the following important fact: the very same key is used both to produce a HMAC value over some message, and to verify the HMAC value over the message.