C Requires Chilkat v11.6.0+

Hash a Password with Argon2 (Defaults)

Demonstrates Crypt2.Argon2HashPassword, which hashes a password with Argon2 and returns a PHC-format string. Passing an empty options string uses all defaults, including a random salt.

Background. Argon2 (RFC 9106) is a memory-hard function that is deliberately expensive in CPU time and memory, which is what makes brute-forcing the password space costly. The argon2id variant is recommended unless there is a specific reason to choose argon2i or argon2d. The returned PHC string records the variant, version, cost parameters, salt, and hash — everything needed to verify the password later. Store the whole string.

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#include <C_CkCrypt2.h>

void ChilkatSample(void)
    {
    HCkCrypt2 crypt;
    const char *password;
    const char *phcHash;

    crypt = CkCrypt2_Create();

    //  The password should come from a secure source rather than being hard-coded.
    password = "correct horse battery staple";

    //  Hash the password using all defaults by passing an empty options string.  The defaults are
    //  Argon2id, version 19, 3 iterations, 64 MB of memory, 1 lane, a 32-byte hash, and a 16-byte random
    //  salt.  A random salt is generated automatically, which is what should normally happen.
    phcHash = CkCrypt2_argon2HashPassword(crypt,password,"");
    if (CkCrypt2_getLastMethodSuccess(crypt) == FALSE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkCrypt2_Dispose(crypt);
        return;
    }

    //  The returned PHC-format string records the variant, version, cost parameters, salt, and hash --
    //  everything needed to verify the password later.  Store the whole string.
    printf("%s\n",phcHash);


    CkCrypt2_Dispose(crypt);

    }