go包：crypto-rsa非对称加密

1. 维基百科释义

RSA加密算法是一种非对称加密算法，在公开密钥加密和电子商业中被广泛使用。RSA是由罗纳德·李维斯特（Ron Rivest）、阿迪·萨莫尔（Adi Shamir）和[伦纳德·阿德曼（Leonard Adleman）在1977年一起提出的。当时他们三人都在[麻省理工学院工作。RSA 就是他们三人姓氏开头字母拼在一起组成的。

2.生成密钥

RSA私钥存在PKCS1和PKCS8两种格式，通过openssl生成的私钥格式为PKCS1,公钥格式为PKCS8。

2.1 使用`openssl`命令

1.生成私钥(`PKCS1`格式)

# 生成私钥
➜ openssl genrsa -out private_ssl.pem 1024
Generating RSA private key, 1024 bit long modulus
.......++++++
.............................................++++++
e is 65537 (0x10001)
# 查看私钥
➜ cat private_ssl.pem
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

2.生成公钥(`PKCS8格式`)

# 生成公钥
➜ openssl rsa -in private_ssl.pem -pubout -out public_ssl.pem
writing RSA key
# 查看公钥
➜ cat public_ssl.pem
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDSgkiwisLr7yTuKnn6jANvRXRf
nA9PINojpPiegMkv/mnScEvMczP8OZjpFrsjSKFnlc6OX04O+4G3GuBMjc75wQw7
9auM4WMJtSh3PAWiBGu6WotoAqZFbWRnIzk2Wjw1xSJxpOUa0ed1plU/jut1dKgD
Ti4q+BDqGizI2JeJdQIDAQAB
-----END PUBLIC KEY-----

3. 私钥PKCS1转PKCS8

➜ openssl pkcs8 -topk8 -inform pem -in private_ssl.pem -outform PEM -nocrypt
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----

3.读取密钥

3.1 代码

// 读取PKCS1格式私钥
func ReadRSAPKCS1PrivateKey(path string) (*rsa.PrivateKey, error) {
    // 读取文件
    context, err := ioutil.ReadFile(path)
    if err != nil {
        return nil, err
    }
    // pem解码
    pemBlock, _ := pem.Decode(context)
    // x509解码
    privateKey, err := x509.ParsePKCS1PrivateKey(pemBlock.Bytes)
    return privateKey, err
}
// 读取公钥(包含PKCS1和PKCS8)
func ReadRSAPublicKey(path string) (*rsa.PublicKey, error) {
    var  err error
    // 读取文件
    readFile, err := ioutil.ReadFile(path)
    if err != nil {
        return nil, err
    }
    // 使用pem解码
    pemBlock, _ := pem.Decode(readFile)
    var pkixPublicKey interface{}
    if pemBlock.Type == "RSA PUBLIC KEY" {
        // -----BEGIN RSA PUBLIC KEY-----
        pkixPublicKey, err = x509.ParsePKCS1PublicKey(pemBlock.Bytes)
    } else if pemBlock.Type == "PUBLIC KEY" {
        // -----BEGIN PUBLIC KEY-----
        pkixPublicKey, err = x509.ParsePKIXPublicKey(pemBlock.Bytes)
    }
    if err != nil {
        return nil,err
    }
    publicKey := pkixPublicKey.(*rsa.PublicKey)
    return publicKey, nil
}

3.2 测试

// 读取密钥
func TestReadKey(t *testing.T) {
    // pkcs1格式-私钥
    privatePKCS1KeyPath := "../../tmp/private_ssl.pem"
    privatePKCS1Key, err := crypto.ReadRSAPKCS1PrivateKey(privatePKCS1KeyPath)
    if err != nil {
        t.Error(err)
    }
    fmt.Printf("PKCS1私钥: %#v\n",privatePKCS1Key)
    // pkcs8格式-公钥
    publicPKCS8KeyPath := "../../tmp/public_ssl.pem"
    publicPKCS8Key, err := crypto.ReadRSAPublicKey(publicPKCS8KeyPath)
    if err != nil {
        t.Error(err)
    }
    fmt.Printf("PKCS8公钥: %#v\n",publicPKCS8Key)
}

4.加密

4.1 代码

// 加密(使用公钥加密)
func RSAEncrypt(data, publicKeyPath string) (string, error) {
    // 获取公钥
  // ReadRSAPublicKey代码在 【3.读取密钥】
    rsaPublicKey, err := ReadRSAPublicKey(publicKeyPath)
    if err != nil {
        return "", err
    }
    // 加密
    encryptPKCS1v15, err := rsa.EncryptPKCS1v15(rand.Reader, rsaPublicKey, []byte(data))
    if err != nil {
        return "",err
    }
    // 把加密结果转成Base64
    encryptString := base64.StdEncoding.EncodeToString(encryptPKCS1v15)
    return encryptString, err
}

4.2 测试

// 加密测试
func TestRsaEncrypt(t *testing.T) {
    publicKeyPath := "../../tmp/public_ssl.pem"
    data := "123456"
    encrypt, err := crypto.RSAEncrypt(data, publicKeyPath)
    if err != nil {
        t.Error(err)
    }
    fmt.Printf("加密结果:%v \n",encrypt)
}
/** 输出
=== RUN   TestRsaEncrypt
加密结果:SRYyBXd4p+wUeTZ5478g+hW2P3OvqhYMyPwW/j91SappgxMWC/O3vCG2aVTcAHknUkK2oEs6e28deKuOvOkjSWl/jnXFDCkXklgbgnXJtfu2FjP9jXhG2b6/Eo3okxLvLXZtkaRAgZKNbbKkeiNASUO4IidkoNrnI4aOuuuVIOY= 
--- PASS: TestRsaEncrypt (0.00s)
PASS
*/

5.解密

5.1 代码

// 解密(使用私钥解密)
func RSADecrypt(base64data,privateKeyPath string) (string,error) {
    // data反解base64
    decodeString, err := base64.StdEncoding.DecodeString(base64data)
    if err != nil {
        return "", err
    }
    // 读取密钥
    rsaPrivateKey, err := ReadRSAPKCS1PrivateKey(privateKeyPath)
    if err != nil {
        return "", err
    }
    // 解密
    decryptPKCS1v15, err := rsa.DecryptPKCS1v15(rand.Reader, rsaPrivateKey, decodeString)
    return string(decryptPKCS1v15),err
}

5.2 测试

// 解密测试
func TestRsaDecrypt(t *testing.T) {
    privateKeyPath := "../../tmp/private_ssl.pem"
    data := "pUYa4set6XkBshfio5g2hzPx1tA67sxEvJBpJiuK3McJ9cPJAXzuRkWIy4s6cDQOhrPUaNXhr3M3WLHH19/eaqcNZz1yOFZwgGKmkWtdmygtLB/wrDant9uRfXrvzlV9iMq+cUlqsrwuCa0wcGEBNHRhIJOQSTs+SxaRTeoRCbU="
    encrypt, err := crypto.RSADecrypt(data, privateKeyPath)
    if err != nil {
        t.Error(err)
    }
    fmt.Printf("解密结果:%v \n",encrypt)
}
/** 输出
=== RUN   TestRsaDecrypt
解密结果:123456 
--- PASS: TestRsaDecrypt (0.00s)
PASS
*/

6.数据签名

6.1 加签

a. 代码

// 对数据进行数字签名
func GetRSASign(data, privateKeyPath string) (string, error) {
    // 读取私钥
    privateKey, err := ReadRSAPKCS1PrivateKey(privateKeyPath)
    if err != nil {
        return "", err
    }
    // 计算Sha1散列值
    hash := sha256.New()
    hash.Write([]byte(data))
    sum := hash.Sum(nil)
    // 从1.5版本规定，使用RSASSA-PKCS1-V1_5-SIGN 方案计算签名
    signPKCS1v15, err := rsa.SignPKCS1v15(rand.Reader, privateKey, crypto.SHA256, sum)
    // 结果转成base64
    toString := base64.StdEncoding.EncodeToString(signPKCS1v15)
    return toString, err
}

b. 测试

// 数据加签
func TestAddSign(t *testing.T) {
    privateKeyPath := "../../tmp/private_ssl.pem"
    data := "123456"
    sign, err := crypto.GetRSASign(data,privateKeyPath)
    if err != nil {
        t.Error(err)
    }
    fmt.Printf("数据签名: %v \n",sign)
}
/** 输出
=== RUN   TestAddSign
数据签名: QnGqGbIqoHjJG1l+JiaOKWBdX+h00lnKCoO2rTYKIro9hoaDj7nqmu+Mxsuo+2jumicvCNBZNOpMzYryjZf0x7Q4ycLBtqtCWuFRasiInUO7Avy19LRTjdMf2xw9968vilB/xEAQ53JXIDUVvCsMxTfpHI9oRiWEGXWNkhfkjkQ= 
--- PASS: TestAddSign (0.00s)
PASS
*/

6.2 验签