| crypto/cipher | Package cipher implements standard block cipher modes that can be wrapped around low-level block cipher implementations. |
| encoding/binary | Package binary implements simple translation between numbers and byte sequences and encoding and decoding of varints. |
| errors | Package errors implements functions to manipulate errors. |
| golang.org/x/crypto/internal/alias | Package alias implements memory aliasing tests. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |