AppendDESPadding appends an 0x80 bytes to data and other zero bytes to make the result length multiple of 8.

DeriveKey derives a key from the current cardKey using the sequence number receive from the card and the purpose (ENC/MAC).

EncryptICV encrypts an ICV with the specified macKey.

Mac3DES generates the triple DES mac of data using the specified key and icv.

MacFull3DES generates a full triple DES mac.

VerifyCryptogram verifies the cryptogram sends from the card to ensure that card and client are using the same keys to communicate.

DerivationPurposeEnc defines 2 bytes used when deriving a encoding key.

DerivationPurposeMac defines 2 bytes used when deriving a mac key.

NullBytes8 defined a slice of 8 zero bytes mostrly used as IV in cryptographic functions.