C

RSA Encrypt Hash using SHA256 hash function and SHA1 mask function

See more RSA Examples

How can this Javascript be duplicated using Chilkat?

function a(e, t) {
                var r = s.pki.publicKeyFromPem(e)
                  , n = r.encrypt(t, "RSA-OAEP", {
                    md: s.md.sha256.create(),
                    mgf1: {
                        md: s.md.sha1.create()
                    }
                });
                return s.util.encode64(n)
            }

Note: The OAEP padding uses random bytes in the padding, and therefore each time encryption happens, even using the same data and key, the result will be different -- but still valid. One should not expect to get the same output.

C

#include <C_CkPublicKey.h>
#include <C_CkStringBuilder.h>
#include <C_CkCrypt2.h>
#include <C_CkRsa.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPublicKey pubkey;
    HCkStringBuilder sbPem;
    BOOL bCrlf;
    const char *originalData;
    HCkCrypt2 crypt;
    const char *hashBase64;
    HCkRsa rsa;
    BOOL bUsePrivateKey;
    const char *encryptedStr;

    success = FALSE;

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

    pubkey = CkPublicKey_Create();

    sbPem = CkStringBuilder_Create();
    bCrlf = TRUE;
    CkStringBuilder_AppendLine(sbPem,"-----BEGIN PUBLIC KEY-----",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA33TqqLR3eeUmDtHS89qF",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"04DDnEFGAf+kDQiNSe2ZtqC7bnIc8+KSG/qOGQIVaay4Ucr6ovDkykO5Hxn7OU7s",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"Jp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwF",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"wnxCsU5+UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUE",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"f0YN3/Q0auBkdbDR/ES2PbgKTJdkjc/rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1W",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"SwIDAQAB",bCrlf);
    CkStringBuilder_AppendLine(sbPem,"-----END PUBLIC KEY-----",bCrlf);

    // Load the public key object from the PEM. 
    success = CkPublicKey_LoadFromString(pubkey,CkStringBuilder_getAsString(sbPem));
    if (success == FALSE) {
        printf("%s\n",CkPublicKey_lastErrorText(pubkey));
        CkPublicKey_Dispose(pubkey);
        CkStringBuilder_Dispose(sbPem);
        return;
    }

    originalData = "This is the original data to be SHA-256 hashed and RSA encrypted.";

    // First we SHA-256 hash the original data to get the hash in base64 format:
    crypt = CkCrypt2_Create();
    CkCrypt2_putHashAlgorithm(crypt,"SHA-256");
    CkCrypt2_putEncodingMode(crypt,"base64");
    hashBase64 = CkCrypt2_hashStringENC(crypt,originalData);

    // Setup RSA to use OAEP padding with SHA-1 for the mask function.
    rsa = CkRsa_Create();
    CkRsa_putPkcsPadding(rsa,FALSE);
    CkRsa_putOaepHash(rsa,"SHA256");
    CkRsa_UsePublicKey(rsa,pubkey);
    CkRsa_putEncodingMode(rsa,"base64");

    // We can provide a binary encoding mode, such as "base64", "hex", "base64url", etc.
    // for the Charset property.   The Charset property was previously limited to character encodings, such as
    // "utf-8", "iso-8859-1", etc.  If a binary encoding is used, then the string passed in is decoded to the binary
    // bytes as indicated.  (If an actual charset, such as "utf-8" is used, then the input string is converted to the
    // byte representation of the charset, and then encrypted.)

    // Given that a hash is composed of non-text binary bytes, we'll set the Charset property equal to "base64" 
    // (because we have the base64 hash from above).
    CkRsa_putCharset(rsa,"base64");

    // Note: The OAEP padding uses random bytes in the padding, and therefore each time encryption happens,
    // even using the same data and key, the result will be different --  but still valid.  One should not expect
    // to get the same output.
    bUsePrivateKey = FALSE;
    encryptedStr = CkRsa_encryptStringENC(rsa,hashBase64,bUsePrivateKey);
    if (CkRsa_getLastMethodSuccess(rsa) == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkPublicKey_Dispose(pubkey);
        CkStringBuilder_Dispose(sbPem);
        CkCrypt2_Dispose(crypt);
        CkRsa_Dispose(rsa);
        return;
    }

    printf("Base64 RSA encrypted output: %s\n",encryptedStr);


    CkPublicKey_Dispose(pubkey);
    CkStringBuilder_Dispose(sbPem);
    CkCrypt2_Dispose(crypt);
    CkRsa_Dispose(rsa);

    }