Question

What are the parameters n, e, d, p, q represent in below RSA structure for openssl ?

struct rsa_st
    {
    /* The first parameter is used to pickup errors where
     * this is passed instead of aEVP_PKEY, it is set to 0 */
    int pad;
    long version;
    const RSA_METHOD *meth;
    /* functional reference if 'meth' is ENGINE-provided */
    ENGINE *engine;
    BIGNUM *n;
    BIGNUM *e;
    BIGNUM *d;
    BIGNUM *p;
    BIGNUM *q;
    BIGNUM *dmp1;
    BIGNUM *dmq1;
    BIGNUM *iqmp;
    /* be careful using this if the RSA structure is shared */
    CRYPTO_EX_DATA ex_data;
    int references;
    int flags;

    /* Used to cache montgomery values */
    BN_MONT_CTX *_method_mod_n;
    BN_MONT_CTX *_method_mod_p;
    BN_MONT_CTX *_method_mod_q;

    /* all BIGNUM values are actually in the following data, if it is not
     * NULL */
    char *bignum_data;
    BN_BLINDING *blinding;
    BN_BLINDING *mt_blinding;
    };

Answer 1

as you can see from the openssl official page, their numbers with specific roles in calculating the ciphertext, OpenSSL official documentation

I suggest you to take a gander at it,
Bye!

EDIT 2018-07-27: update url
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