Go

RSA Sign with PKCS8 Encrypted Key

See more RSA Examples

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature (and then verify it). Go

    success := false

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    privKey := chilkat.NewPrivateKey()

    // Load the private key from an RSA PEM file:
    success = privKey.LoadAnyFormatFile("raul_privateKey.key","a0123456789")
    if success == false {
        fmt.Println(privKey.LastErrorText())
        privKey.DisposePrivateKey()
        return
    }

    rsa := chilkat.NewRsa()

    // Import the private key into the RSA component:
    success = rsa.UsePrivateKey(privKey)
    if success == false {
        fmt.Println(rsa.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        return
    }

    // This example will sign a string, and receive the signature
    // in a hex-encoded string.  Therefore, set the encoding mode
    // to "hex":
    rsa.SetEncodingMode("hex")

    strData := "This is the string to be signed."

    // Sign the string using the sha256 hash algorithm.
    // Other valid choices are sha1, sha384, sha512 and others.
    hexSig := rsa.SignStringENC(strData,"sha256")
    if rsa.LastMethodSuccess() == false {
        fmt.Println(rsa.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        return
    }

    fmt.Println(*hexSig)

    // Now verify with the public key.
    // This example shows how to use the public key from 
    // a digital certificate (.cer file)
    cert := chilkat.NewCert()
    success = cert.LoadFromFile("raul_publicKey.cer")
    if success == false {
        fmt.Println(cert.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        cert.DisposeCert()
        return
    }

    pubKey := chilkat.NewPublicKey()
    cert.GetPublicKey(pubKey)

    rsa2 := chilkat.NewRsa()
    success = rsa2.UsePublicKey(pubKey)
    if success == false {
        fmt.Println(rsa2.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        cert.DisposeCert()
        pubKey.DisposePublicKey()
        rsa2.DisposeRsa()
        return
    }

    // Verify the signature against the original data:
    rsa2.SetEncodingMode("hex")
    success = rsa2.VerifyStringENC(strData,"sha256",*hexSig)
    if success == false {
        fmt.Println(rsa2.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        cert.DisposeCert()
        pubKey.DisposePublicKey()
        rsa2.DisposeRsa()
        return
    }

    fmt.Println("Signature verified!")

    // Verify with incorrect data:
    success = rsa2.VerifyStringENC("something else","sha256",*hexSig)
    if success != true {
        fmt.Println("Signature not verified! (which was expected in this case)")
    } else {
        fmt.Println("Hmmm... that's not right...")
    }


    privKey.DisposePrivateKey()
    rsa.DisposeRsa()
    cert.DisposeCert()
    pubKey.DisposePublicKey()
    rsa2.DisposeRsa()