blindrsa

// Setup (offline)

// Server: generate an RSA keypair.
sk, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
	fmt.Printf("failed to generate RSA key: %v", err)
	return
}
pk := &sk.PublicKey
server := NewSigner(sk)

// Client: stores Server's public key.
client, err := NewClient(SHA384PSSRandomized, pk)
if err != nil {
	fmt.Printf("failed to invoke a client: %v", err)
	return
}

// Protocol (online)

// Client prepares the message to be signed.
msg := []byte("alice and bob")
preparedMessage, err := client.Prepare(rand.Reader, msg)
if err != nil {
	fmt.Printf("client failed to prepare the message: %v", err)
	return
}

// Client blinds a message.
blindedMsg, state, err := client.Blind(rand.Reader, preparedMessage)
if err != nil {
	fmt.Printf("client failed to generate blinded message: %v", err)
	return
}

// Server signs a blinded message, and produces a blinded signature.
blindedSignature, err := server.BlindSign(blindedMsg)
if err != nil {
	fmt.Printf("server failed to sign: %v", err)
	return
}

// Client build a signature from the previous state and blinded signature.
signature, err := client.Finalize(state, blindedSignature)
if err != nil {
	fmt.Printf("client failed to obtain signature: %v", err)
	return
}

// Client build a signature from the previous state and blinded signature.
ok := client.Verify(preparedMessage, signature)

fmt.Printf("Valid signature: %v", ok == nil)

Output:

Valid signature: true