(Go) RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature.

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    // 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 .key file:
    success := privKey.LoadPemFile("privateKey.key")
    if success != true {
        fmt.Println(privKey.LastErrorText())
        privKey.DisposePrivateKey()
        return
    }

    var privKeyXml *string = new(string)
    // Get the private key in XML format:
    privKeyXml = privKey.GetXml()

    rsa := chilkat.NewRsa()

    // Import the private key into the RSA component:
    success = rsa.ImportPrivateKey(*privKeyXml)
    if success != true {
        fmt.Println(rsa.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        return
    }

    // Create the signature as a hex string:
    rsa.SetEncodingMode("hex")

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

    // Sign the string using the sha-1 hash algorithm.
    // Other valid choices are "md2", "sha256", "sha384",
    // "sha512", and "md5".
    hexSig := rsa.SignStringENC(strData,"sha-1")

    fmt.Println(*hexSig)

    // Load a digital certificate from a .cer file:
    cert := chilkat.NewCert()

    success = cert.LoadFromFile("myCert.cer")
    if success != true {
        fmt.Println(cert.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        cert.DisposeCert()
        return
    }

    // pubKey is a PublicKey

    pubKey := cert.ExportPublicKey()

    // Now verify using a separate instance of the RSA object:
    rsa2 := chilkat.NewRsa()

    // Import the public key into the RSA object:
    success = rsa2.ImportPublicKey(*pubKey.GetXml())
    if success != true {
        fmt.Println(rsa2.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        cert.DisposeCert()
        rsa2.DisposeRsa()
        return
    }

    pubKey.DisposePublicKey()

    // The signature is a hex string, so make sure the EncodingMode is correct:
    rsa2.SetEncodingMode("hex")

    // Verify the signature:
    success = rsa2.VerifyStringENC(strData,"sha-1",*hexSig)
    if success != true {
        fmt.Println(rsa2.LastErrorText())
        privKey.DisposePrivateKey()
        rsa.DisposeRsa()
        cert.DisposeCert()
        rsa2.DisposeRsa()
        return
    }

    fmt.Println("Success.")

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