| crypto | Package crypto collects common cryptographic constants. |
| crypto/hmac | Package hmac implements the Keyed-Hash Message Authentication Code (HMAC) as defined in U.S. Federal Information Processing Standards Publication 198. |
| encoding/base32 | Package base32 implements base32 encoding as specified by RFC 4648. |
| encoding/binary | Package binary implements simple translation between numbers and byte sequences and encoding and decoding of varints. |
| hash | Package hash provides interfaces for hash functions. |
| math | Package math provides basic constants and mathematical functions. |
| net/url | Package url parses URLs and implements query escaping. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| time | Package time provides functionality for measuring and displaying time. |