(C) Generate RSA Key and Export to PKCS1 / PKCS8

C example code showing how to generate an RSA public/private key and save to PKCS1 and PKCS8 format files. In a PKCS1 or PKCS8 formatted file, the key is stored in binary ASN.1 format (and ASN.1 is itself written according to DER -- Distinguished Encoding Rules). A PEM file simply contains the binary ASN.1 base64 encoded and delimited by BEGIN/END lines. PKCS1 format files are never encrypted. PKCS8 can be encrypted or unencrypted. Public keys are never encrypted (there is no need). Private keys *should* always be encrypted - unless perhaps the unencrypted private key is obtained and itself stored in some sort of secure place.

Note: This example requires Chilkat v11.0.0 or greater.

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#include <C_CkRsa.h>
#include <C_CkPrivateKey.h>
#include <C_CkPublicKey.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkRsa rsa;
    HCkPrivateKey privKey;
    HCkPublicKey pubKey;
    const char *pubKeyPem;
    const char *pubKeyPkcs8Base64;
    const char *pubKeyPkcs1Base64;
    const char *privKeyPem;
    const char *privKeyEncPem;
    const char *privKeyPkcs1Base64;
    const char *privKeyPkcs8Base64;

    success = FALSE;

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

    rsa = CkRsa_Create();

    // Generate a 2048-bit key.  Chilkat RSA supports
    // key sizes ranging from 512 bits to 8192 bits.
    privKey = CkPrivateKey_Create();
    success = CkRsa_GenKey(rsa,2048,privKey);
    if (success == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkRsa_Dispose(rsa);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    // Get the public key
    pubKey = CkPublicKey_Create();
    CkPrivateKey_ToPublicKey(privKey,pubKey);

    // Get the public key as a PKCS8 PEM string
    pubKeyPem = CkPublicKey_getPem(pubKey,FALSE);
    printf("%s\n",pubKeyPem);

    // Get the public key in PKCS8 format, in a Base64 encoded string.
    pubKeyPkcs8Base64 = CkPublicKey_getEncoded(pubKey,FALSE,"base64");
    printf("%s\n",pubKeyPkcs8Base64);

    // Get the public key in PKCS1 format, in a Base64 encoded string.
    pubKeyPkcs1Base64 = CkPublicKey_getEncoded(pubKey,TRUE,"base64");
    printf("%s\n",pubKeyPkcs1Base64);

    // Get the private key in a PKCS8 PEM string.
    privKeyPem = CkPrivateKey_getPkcs8Pem(privKey);
    printf("%s\n",privKeyPem);

    // Get the private key in a PKCS8 encrypted PEM string.
    privKeyEncPem = CkPrivateKey_getPkcs8EncryptedPem(privKey,"myPassword");
    printf("%s\n",privKeyEncPem);

    // Get the private key in PKCS1 Base64 format
    privKeyPkcs1Base64 = CkPrivateKey_getPkcs1ENC(privKey,"base64");
    printf("%s\n",privKeyPkcs1Base64);

    // Get the private key in PKCS8 Base64 format
    privKeyPkcs8Base64 = CkPrivateKey_getPkcs8ENC(privKey,"base64");
    printf("%s\n",privKeyPkcs8Base64);

    // Save to PKCS1 / PKCS8 / PEM files...

    // Save the public key to PKCS8 binary DER
    success = CkPublicKey_SaveDerFile(pubKey,FALSE,"pubKey_pkcs8.der");

    // Save the public key to PKCS1 binary DER
    success = CkPublicKey_SaveDerFile(pubKey,"pubKey_pkcs1.der");

    // Save the private key to unencrypted binary PKCS1 DER.
    // Note: PKCS1 is never found in an encrypted format. 
    success = CkPrivateKey_SavePkcs1File(privKey,"privKey_pkcs1.der");

    // Save the private key to unencrypted binary PKCS8
    success = CkPrivateKey_SavePkcs8File(privKey,"privKey_pkcs8.der");

    // Save the private key to encrypted binary PKCS8
    success = CkPrivateKey_SavePkcs8EncryptedFile(privKey,"myPassword","privKey_enc_pkcs8.der");

    // Save the private key to unencrypted PKCS8 PEM
    success = CkPrivateKey_SavePkcs8PemFile(privKey,"privKey.pem");

    // Save the private key to encrypted PKCS8 PEM
    success = CkPrivateKey_SavePkcs8EncryptedPemFile(privKey,"myPassword","privKey_enc.pem");


    CkRsa_Dispose(rsa);
    CkPrivateKey_Dispose(privKey);
    CkPublicKey_Dispose(pubKey);

    }