| crypto | Package crypto collects common cryptographic constants. |
| 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/ecdh | Package ecdh implements Elliptic Curve Diffie-Hellman over NIST curves and Curve25519. |
| crypto/rand | Package rand implements a cryptographically secure random number generator. |
| 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/chacha20poly1305 | Package chacha20poly1305 implements the ChaCha20-Poly1305 AEAD and its extended nonce variant XChaCha20-Poly1305, as specified in RFC 8439 and draft-irtf-cfrg-xchacha-01. |
| golang.org/x/crypto/hkdf | Package hkdf implements the HMAC-based Extract-and-Expand Key Derivation Function (HKDF) as defined in RFC 5869. |
| math/bits | Package bits implements bit counting and manipulation functions for the predeclared unsigned integer types. |