| crypto | Package crypto collects common cryptographic constants. |
| encoding/pem | Package pem implements the PEM data encoding, which originated in Privacy Enhanced Mail. |
| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/google/certificate-transparency-go/x509 | Package x509 parses X.509-encoded keys and certificates. |
| github.com/google/trillian/crypto/keys/der | Package der contains functions for marshaling and unmarshaling keys in DER format. |
| github.com/google/trillian/crypto/keyspb | |
| io/ioutil | Package ioutil implements some I/O utility functions. |