| crypto | Package crypto collects common cryptographic constants. |
| crypto/ecdsa | Package ecdsa implements the Elliptic Curve Digital Signature Algorithm, as defined in FIPS 186-3. |
| crypto/elliptic | Package elliptic implements several standard elliptic curves over prime fields. |
| crypto/rand | Package rand implements a cryptographically secure pseudorandom number generator. |
| crypto/rsa | Package rsa implements RSA encryption as specified in PKCS#1. |
| crypto/sha1 | Package sha1 implements the SHA1 hash algorithm as defined in RFC 3174. |
| crypto/x509 | Package x509 parses X.509-encoded keys and certificates. |
| crypto/x509/pkix | Package pkix contains shared, low level structures used for ASN.1 parsing and serialization of X.509 certificates, CRL and OCSP. |
| encoding/asn1 | Package asn1 implements parsing of DER-encoded ASN.1 data structures, as defined in ITU-T Rec X.690. |
| errors | Package errors implements functions to manipulate errors. |
| math/big | Package big implements arbitrary-precision arithmetic (big numbers). |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| time | Package time provides functionality for measuring and displaying time. |