| crypto/md5 | Package md5 implements the MD5 hash algorithm as defined in RFC 1321. |
| encoding/binary | Package binary implements simple translation between numbers and byte sequences and encoding and decoding of varints. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| hash | Package hash provides interfaces for hash functions. |
| 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. |