| crypto/rand | Package rand implements a cryptographically secure random number generator. |
| encoding/hex | Package hex implements hexadecimal encoding and decoding. |
| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| io | Package io provides basic interfaces to I/O primitives. |
| io/ioutil | Package ioutil implements some I/O utility functions. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| syscall | Package syscall contains an interface to the low-level operating system primitives. |