Simple example

dsa_crypto_example.go

package main
import "crypto/dsa"
import "crypto/rand"
import "fmt"
import "math/big"


func SignatureGenerateServerKey() *dsa.PrivateKey {
        priv := dsa.PrivateKey{}
        dsa.GenerateParameters(&priv.Parameters, rand.Reader, dsa.L3072N256)
        dsa.GenerateKey(&priv, rand.Reader)
        return &priv
}

func SignatureSign(hash []byte, priv *dsa.PrivateKey) (r, s []byte, err error) {
        ri, si, err := dsa.Sign(rand.Reader, priv, hash)
        if err != nil {
                return nil, nil, err
        }
        r, err = ri.MarshalJSON()
        if err != nil {
                return nil, nil, err
        }
        s, err = si.MarshalJSON()
        if err != nil {
                return nil, nil, err
        }
        return r, s, nil
}

func SignatureVerify(hash []byte, priv *dsa.PrivateKey, r []byte, s []byte) bool {
        var ri, si big.Int
        if ri.UnmarshalJSON(r) != nil {
                return false
        }
        if si.UnmarshalJSON(s) != nil {
                return false
        }
    return dsa.Verify(&priv.PublicKey, hash, &ri, &si)
}

func main() {
        priv := SignatureGenerateServerKey()
        hash := []byte("this is a message")
        r, s, err := SignatureSign(hash, priv)
                if err != nil {
                fmt.Println(err)
                return
        }
        fmt.Println(string(r))
        fmt.Println(string(s))
        if SignatureVerify(hash, priv, r, s) {
                fmt.Println("Signature pass")
        } else {
                fmt.Println("Signature fail")
        }
}