Imports of package pubkeypin

PathSynopsis
crypto/sha256Package sha256 implements the SHA224 and SHA256 hash algorithms as defined in FIPS 180-4.
crypto/x509Package x509 implements a subset of the X.509 standard.
encoding/hexPackage hex implements hexadecimal encoding and decoding.
github.com/pkg/errorsPackage errors provides simple error handling primitives.
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.