| crypto | Package crypto collects common cryptographic constants. |
| crypto/rand | Package rand implements a cryptographically secure random number generator. |
| 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. |
| golang.org/x/crypto/ssh | Package ssh implements an SSH client and server. |
| hash | Package hash provides interfaces for hash functions. |
| io | Package io provides basic interfaces to I/O primitives. |