crypto

Overview ¶

Package spake2 implements the SPAKE2 password-authenticated key exchange protocol as defined in RFC 9382.

SPAKE2 enables two parties that share a password to derive a strong shared key without disclosing the password. This implementation follows the RFC 9382 specification and provides support for various elliptic curve groups.

Basic usage:

// Initialize the protocol with a shared password
password := []byte("password123")
opts := spake2.DefaultOptions()

// Create client and server instances
client := spake2.NewClient(password, opts)
server := spake2.NewServer(password, opts)

// Generate the first message from client (A)
msgA, err := client.Start()
if err != nil {
    // handle error
}

// Process client's message and generate response from server (B)
msgB, err := server.Exchange(msgA)
if err != nil {
    // handle error
}

// Complete the exchange on client side
clientConfirm, err := client.Finish(msgB)
if err != nil {
    // handle error
}

// Complete the exchange on server side
serverConfirm, err := server.Confirm(clientConfirm)
if err != nil {
    // handle error
}

// Send server confirmation to client
err = client.Verify(serverConfirm)
if err != nil {
    // handle error
}

// Both sides now have the same shared key
clientKey := client.SharedKey()
serverKey := server.SharedKey()

The implementation supports different elliptic curve groups and can be configured with custom parameters if needed.