pem.Decode-在给定id_rsa.pem内容时返回nil

I'm trying to use rsa package for encrypt and decrypt with public and private keys.

func main() {
    flag.Parse()

    text := "my super secret"
    glog.Infof("Original text: %s
", text)

    glog.Infoln("Loading public key..")
    pubKey, err := loadPublicKey("id_rsa.pub")
    if err == nil {
        glog.Infoln("SUCCESS!")
    } else {
        glog.Errorln("LOOSE =(")
    }

    etext, err := encrypt([]byte(text), pubKey)
    if err != nil {
        glog.Errorf("Can't encrypt text: %+v
", err)
    }
    glog.Infof("Encrypted text: %s
", etext)

    glog.Infoln("Loading private key..")
    privKey, err := loadPrivateKey("id_rsa")
    if err == nil {
        glog.Infoln("SUCCESS!")
    } else {
        glog.Errorln("LOOSE =(")
    }

    dtext, err := decrypt(etext, privKey)
    if err != nil {
        glog.Errorf("Can't decrypt text: %+v
", err)
    }
    glog.Infof("Decrypted text: %s
", dtext)

    glog.Flush()
}

func loadPublicKey(path string) (*rsa.PublicKey, error) {
    data, err := ioutil.ReadFile(path)
    if err != nil {
        return nil, err
    }

    block, _ := pem.Decode(data)
    if block == nil {
        return nil, fmt.Errorf("no key found
")
    }

    if block.Type != "PUBLIC KEY" {
        return nil, fmt.Errorf("invalid key type - %s
", block.Type)
    }

    pubKey, err := x509.ParsePKIXPublicKey(block.Bytes)
    if err != nil {
        return nil, fmt.Errorf("can't parse key - %+v
", err)
    }

    return pubKey.(*rsa.PublicKey), nil
}

func loadPrivateKey(path string) (*rsa.PrivateKey, error) {
    data, err := ioutil.ReadFile(path)
    if err != nil {
        return nil, err
    }

    block, _ := pem.Decode(data)
    if block == nil {
        return nil, fmt.Errorf("no key found
")
    }

    if block.Type != "PRIVATE KEY" {
        return nil, fmt.Errorf("invalid key type - %s
", block.Type)
    }

    return x509.ParsePKCS1PrivateKey(block.Bytes)
}

func encrypt(data []byte, pubKey *rsa.PublicKey) ([]byte, error) {
    return rsa.EncryptPKCS1v15(rand.Reader, pubKey, data)
}

func decrypt(data []byte, privKey *rsa.PrivateKey) ([]byte, error) {
    return rsa.DecryptPKCS1v15(rand.Reader, privKey, data)
}

But I have an error in rsa.EncryptPKCS1v15:

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x0 pc=0x5c16c]

goroutine 1 [running]:
crypto/rsa.EncryptPKCS1v15(0x11641f8, 0xc8200762a0, 0x0, 0xc82004ddc8, 0xf, 0x20, 0x0, 0x0, 0x0, 0x0, ...)
    /usr/local/go/src/crypto/rsa/pkcs1v15.go:32 +0x5c
main.encrypt(0xc82004ddc8, 0xf, 0x20, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
    /Users/cnaize/Dropbox/develop/gocode/src/test/main.go:132 +0x87
main.main()
    /Users/cnaize/Dropbox/develop/gocode/src/test/main.go:67 +0x3b8

Why where is the error? How to resolve this?

EDITED:
thanks, now I understand the problem - in loadPublicKey("id_rsa.pub") pem.Decode(data) returns nil block.
What is the right way to parse ssh keys?