Package hmac implements the Keyed-Hash Message Authentication Code (HMAC) as defined in U.S. Federal Information Processing Standards Publication 198.

Package md5 implements the MD5 hash algorithm as defined in RFC 1321.

Package rand implements a cryptographically secure random number generator.

Package rc4 implements RC4 encryption, as defined in Bruce Schneier's Applied Cryptography.

Package rsa implements RSA encryption as specified in PKCS #1 and RFC 8017.

Package sha1 implements the SHA-1 hash algorithm as defined in RFC 3174.

Package sha256 implements the SHA224 and SHA256 hash algorithms as defined in FIPS 180-4.

Package sha512 implements the SHA-384, SHA-512, SHA-512/224, and SHA-512/256 hash algorithms as defined in FIPS 180-4.

Package subtle implements functions that are often useful in cryptographic code but require careful thought to use correctly.

Package tls partially implements TLS 1.2, as specified in RFC 5246, and TLS 1.3, as specified in RFC 8446.