| crypto | Package crypto collects common cryptographic constants. |
| crypto/cipher | Package cipher implements standard block cipher modes that can be wrapped around low-level block cipher implementations. |
| crypto/internal/boring/sig | Package sig holds “code signatures” that can be called and will result in certain code sequences being linked into the final binary. |
| hash | Package hash provides interfaces for hash functions. |
| sync/atomic | Package atomic provides low-level atomic memory primitives useful for implementing synchronization algorithms. |
| unsafe | Package unsafe contains operations that step around the type safety of Go programs. |