golang 橢圓曲線密碼編譯使用ecdsa

非對稱式加密演算法有RSA、ECDSA，對極大整數做因數分解的難度決定了RSA演算法的可靠性，ECDSA為橢圓曲線密碼編譯演算法，是基於橢圓方程公式，所以安全性要高於RSA。
這裡說下使用ecdsa做簽名和校正，並不講原理；
golang封裝的ecdsa目前只有用私密金鑰加密，公開金鑰做校正，沒有解密環節；所以目前可以應用於數位簽章；
以下為封裝：

/**    通過一個隨機key建立公開金鑰和私密金鑰    隨機key至少為36位 */func getEcdsaKey(randKey string) (*ecdsa.PrivateKey, ecdsa.PublicKey, error){    var err error    var prk *ecdsa.PrivateKey    var puk ecdsa.PublicKey    var curve elliptic.Curve    lenth := len(randKey)    if lenth < 224/8 {        err =errors.New("私密金鑰長度太短，至少為36位！")        return prk,puk,err    }    if lenth > 521/8 + 8 {        curve = elliptic.P521()    }else if lenth > 384/8 + 8 {        curve = elliptic.P384()    }else if lenth > 256/8 + 8 {        curve = elliptic.P256()    }else if lenth > 224/8 + 8 {        curve = elliptic.P224()    }    prk, err = ecdsa.GenerateKey(curve,strings.NewReader(randKey))    if err != nil {        return prk, puk, err    }    puk = prk.PublicKey    return prk, puk, err}/**    對text加密，text必須是一個hash值，例如md5、sha1等    使用私密金鑰prk    使用隨機熵增強加密安全，安全依賴於此熵，randsign    返回加密結果，結果為數位憑證r、s的序列化後拼接，然後用hex轉換為string */func sign(text []byte,randSign string,prk *ecdsa.PrivateKey) (string, error) {    r, s, err := ecdsa.Sign(strings.NewReader(randSign), prk, text)    if err != nil {        return "", err    }    rt, err := r.MarshalText()    if err != nil {        return "", err    }    st, err := s.MarshalText()    if err != nil {        return "", err    }    var b bytes.Buffer    w := gzip.NewWriter(&b)    defer w.Close()    _, err = w.Write([]byte(string(rt) + "+" + string(st)))    if err != nil {        return "", err    }    w.Flush()    return hex.EncodeToString(b.Bytes()), nil}/**    認證分解    通過hex解碼，分割成數位憑證r，s */func getSign( signature string) (rint, sint big.Int, err error)  {    byterun, err := hex.DecodeString(signature)    if err != nil {        err = errors.New("decrypt error, "+ err.Error())        return    }    r, err := gzip.NewReader(bytes.NewBuffer(byterun))    if err !=  nil {        err = errors.New("decode error,"+err.Error())        return    }    defer r.Close()    buf := make([]byte, 1024)    count, err := r.Read(buf)    if err != nil {        fmt.Println("decode = ",err)        err = errors.New("decode read error," + err.Error())        return    }    rs := strings.Split(string(buf[:count]),"+")    if len(rs) != 2 {        err = errors.New("decode fail")        return    }    err = rint.UnmarshalText([]byte(rs[0]))    if err != nil {        err = errors.New("decrypt rint fail, "+ err.Error())        return    }    err = sint.UnmarshalText([]byte(rs[1]))    if err != nil {        err = errors.New("decrypt sint fail, "+ err.Error())        return    }    return}/**    校正常值內容是否與簽名一致    使用公開金鑰校正簽名和常值內容 */func verify(text []byte, signature string, key ecdsa.PublicKey) (bool, error) {    rint, sint, err :=getSign(signature)    if err != nil {        return false, err    }    result := ecdsa.Verify(&key,text,&rint,&sint)    return result, nil}/**    hash加密    使用md5加密 */func hashtext(text, salt string) ([]byte) {    Md5Inst := md5.New()    Md5Inst.Write([]byte(text))    result := Md5Inst.Sum([]byte(salt))    return result}func main() {    //隨機熵，用於加密安全    randSign := "20180619zafes"    //隨機key，用於建立公開金鑰和私密金鑰    randKey := "fb0f7279c18d4394594fc9714797c9680335a320"    //建立公開金鑰和私密金鑰    prk, puk, err := getEcdsaKey(randKey)    if err != nil {        fmt.Println(err)    }    //hash加密使用md5用到的salt    salt := "131ilzaw"    //待加密的明文    text := "hlloaefaefaefaefaefaefaefhelloaefaefaefaefaefaefaefhelloaefaefaefaefaefaefaef"    //text1 := "hlloaefaefaefaefaefaefaefhelloaefaefaefaefaefaefaefhelloaefaefaefaefaefaefaef1"    //hash取值    htext := hashtext(text,salt)    //htext1 := hashtext(text1,salt)    //hash值編碼輸出    fmt.Println(hex.EncodeToString(htext))    //hash值進行簽名    result, err := sign(htext,randSign,prk)    if err != nil {        fmt.Println(err)    }    //簽名輸出    fmt.Println(result)    //簽名與hash值進行校正    tmp, err := verify(htext,result,puk)    fmt.Println(tmp)}

借鑒使用……