RSA API Example Usage - 2021.1 English

The following example illustrates the usage of the RSA library to encrypt data using the public key and to decrypt the data using private key.

static u32 SecureRsaExample(void)
{
        u32 Index;

        /* RSA signature decrypt with private key */
        /*
         * Initialize the Rsa driver with private key components
         * so that it's ready to use
         */
        XSecure_RsaInitialize(&Secure_Rsa, Modulus, NULL, PrivateExp);


        if(XST_SUCCESS != XSecure_RsaPrivateDecrypt(&Secure_Rsa, Data,
                                                Size, Signature))       {
                xil_printf("Failed at RSA signature decryption\n\r");
                return XST_FAILURE;
        }

        xil_printf("\r\n Decrypted Signature with private key\r\n ");

        for(Index = 0; Index < Size; Index++) {
                xil_printf(" %02x ", Signature[Index]);
        }
        xil_printf(" \r\n ");

        /* Verification if Data is expected */
        for(Index = 0; Index < Size; Index++) {
                if (Signature[Index] != ExpectedSign[Index]) {
                        xil_printf("\r\nError at verification of RSA signature"
                                        " Decryption\n\r");
                        return XST_FAILURE;
                }
        }

        /* RSA signature encrypt with Public key components */

        /*
         * Initialize the Rsa driver with public key components
         * so that it's ready to use
         */

        XSecure_RsaInitialize(&Secure_Rsa, Modulus, NULL, (u8 *)&PublicExp);

        if(XST_SUCCESS != XSecure_RsaPublicEncrypt(&Secure_Rsa, Signature,
                                                Size, EncryptSignatureOut))     {
                xil_printf("\r\nFailed at RSA signature encryption\n\r");
                return XST_FAILURE;
        }
        xil_printf("\r\n Encrypted Signature with public key\r\n ");

        for(Index = 0; Index < Size; Index++) {
                xil_printf(" %02x ", EncryptSignatureOut[Index]);
        }

        /* Verification if Data is expected */
        for(Index = 0; Index < Size; Index++) {
                if (EncryptSignatureOut[Index] != Data[Index]) {
                        xil_printf("\r\nError at verification of RSA signature"
                                        " encryption\n\r");
                        return XST_FAILURE;
                }
        }

        return XST_SUCCESS;
}