| crypto/sha256 | Package sha256 implements the SHA224 and SHA256 hash algorithms as defined in FIPS 180-4. |
| 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/pbkdf2 | Package pbkdf2 implements the key derivation function PBKDF2 as defined in RFC 2898 / PKCS #5 v2.0. |
| math/bits | Package bits implements bit counting and manipulation functions for the predeclared unsigned integer types. |