| bytes | Package bytes implements functions for the manipulation of byte slices. |
| compress/zlib | Package zlib implements reading and writing of zlib format compressed data, as specified in RFC 1950. |
| crypto/aes | Package aes implements AES encryption (formerly Rijndael), as defined in U.S. Federal Information Processing Standards Publication 197. |
| crypto/cipher | Package cipher implements standard block cipher modes that can be wrapped around low-level block cipher implementations. |
| crypto/md5 | Package md5 implements the MD5 hash algorithm as defined in RFC 1321. |
| crypto/rc4 | Package rc4 implements RC4 encryption, as defined in Bruce Schneier's Applied Cryptography. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| 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. |
| 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. |
| unicode | Package unicode provides data and functions to test some properties of Unicode code points. |
| unicode/utf16 | Package utf16 implements encoding and decoding of UTF-16 sequences. |