Imports github.com/cognusion/go-cache-lru github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/prng github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/errors golang.org/x/crypto/hkdf Standard library imports crypto/sha256 crypto/rc4 bytes crypto/hmac crypto/rand crypto/sha1 crypto/subtle encoding/binary encoding/hex errors io io/ioutil net time