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derivation code

Definition​

To properly extract and use the public key embedded in a self-certifying identifier we need to know the cryptographic signing scheme used by the key pair. KERI includes this very compactly in the identifier, by replacing the pad character (a character used to fill a void to able to always end up with a fixed length public key) with a special character that encodes the derivation process. We call this the derivation code.

Example​

For example suppose that the 44 character Base-64 with trailing pad character for the public key is as follows: F5pxRJP6THrUtlDdhh07hJEDKrJxkcR9m5u1xs33bhp= If B is the value of the derivation code then the resultant self-contained string is as follows: BF5pxRJP6THrUtlDdhh07hJEDKrJxkcR9m5u1xs33bhp

Relation with KERI​

All crypto material appears in KERI in a fully qualified representation. This includes a derivation code prepended to the crypto-material.

Example KERI derivation codes​

example derivation code in KERI

Beware​

Key derivation functions are not related to the pre-pended derivation codes used in KERI.