Update README.md

README.md

@@ -292,71 +292,3 @@ The above program can be run to generate multiple fields on the command line:
 ```
 
 The library uses `go modules`; so, it should be straight forward to import and use.
-
-
-### Using the SRP Raw key to derive session keys
-The client and server both derive the same value for RawKey(). This
-is the crux of the SRP protocol. Treat this as a \"master key\".
-It is not advisable to use the RawKey() for encryption purposes. It
-is better to derive a separate key for each direction
-(client-\>server and server-\>client). e.g.,:
-
-```go
-    c2s_k = KDF(rawkey, counter, "C2S")
-    s2s_k = KDF(rawkey, counter, "S2C")
-```
-
-KDF above can be a reputable key derivation function such as PBKDF2
-or Scrypt. The \"counter\" is incremented every time you derive a
-new key.
-
-*I am not a cryptographer*. Please consult your favorite crypto book
-for deriving encryption keys from a master key.
-
-#### Using `scrypt` as the KDF
-Here is a example KDF using `scrypt`:
-
-```go
-    import "golang.org/x/crypto/scrypt"
-
-    // Safe values for Scrypt() parameters
-    const _N int = 65536
-    const _r int = 1024
-    const _p int = 64
-
-    // Kdf derives a 'sz' byte key for use 'usage'
-    func Kdf(key []byte, salt []byte, usage string, sz int) []byte {
-
-        u0 := []byte(usage)
-        pw := append(key, u0...)
-        k, _ := scrypt.Key(pw, salt, _N, _r, _p, sz)
-        return k
-    }
-```
-
-#### Using `argon2` as the KDF
-[Argon](https://tools.ietf.org/html/draft-irtf-cfrg-argon2-03) is
-the new state of the art (2018) key derivation algorithm. The
-`Argon2id` variant is resistant to timing, side-channel and
-Time-memory tradeoff attacks. Here is an example using the `Argon2id`
-variant:
-
-```go
-    import (
-        "runtime"
-        "golang.org/x/crypto/argon2"
-    )
-
-    // safe values for IDKey() borrowed from libsodium
-    const _Time uint32 = 3
-    const _Mem  uint32 = 256 * 1048576  // 256 MB
-
-    // Kdf derives a 'sz' byte key for use 'usage'
-    func Kdf(key, salt []byte, usage string, sz int) []byte {
-        u0 := []byte(usage)
-        pw := append(key, u0...)
-
-        return argon2.IDKey(pw, salt, _Time, _Mem, runtime.NumCPU(), uint32(sz))
-    }
-```
-