As a first step to #3443, we've provided interfaces via the encryption library to create the necessary CryptoConfig structures for encryption/decryption without the need to know internals of the encryption scheme..

We've implemented the following interfaces and updated ctr usage to use it. In addition, there is no longer any use of dcparameters in the codebase outside the encryption library - which uses its internals.

func EncryptWithJwe(pubKeys [][]byte) (CryptoConfig, error) 
func EncryptWithPkcs7(x509s [][]byte) (CryptoConfig, error) 
func EncryptWithGpg(gpgRecipients [][]byte, gpgPubRingFile []byte) (CryptoConfig, error) 
func DecryptWithPrivKeys(privKeys [][]byte, privKeysPasswords [][]byte) (CryptoConfig, error) 
func DecryptWithX509s(x509s [][]byte) (CryptoConfig, error) 
func DecryptWithGpgPrivKeys(gpgPrivKeys, gpgPrivKeysPwds [][]byte) (CryptoConfig, error) 

We are thinking that when the OCI spec gets merged, an option is for the pkg/encryption library to be under the OCI repo. So this would be the interface provided to create the configurations.