| crypto/md5 | Package md5 implements the MD5 hash algorithm as defined in RFC 1321. |
| crypto/rand | Package rand implements a cryptographically secure random number generator. |
| crypto/sha1 | Package sha1 implements the SHA-1 hash algorithm as defined in RFC 3174. |
| encoding/base64 | Package base64 implements base64 encoding as specified by RFC 4648. |
| encoding/csv | Package csv reads and writes comma-separated values (CSV) files. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| net/http | Package http provides HTTP client and server implementations. |
| net/url | Package url parses URLs and implements query escaping. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| time | Package time provides functionality for measuring and displaying time. |