RSA_padding_add_PKCS1_type_1,
       RSA_padding_check_PKCS1_type_1,
       RSA_padding_add_PKCS1_type_2,
       RSA_padding_check_PKCS1_type_2,
       RSA_padding_add_PKCS1_OAEP, RSA_padding_check_PKCS1_OAEP,
       RSA_padding_add_SSLv23, RSA_padding_check_SSLv23,
       RSA_padding_add_none, RSA_padding_check_none - asymmetric
       encryption padding


SYNOPSIS

        #include <openssl/rsa.h>

        int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
           unsigned char *f, int fl);

        int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
           unsigned char *f, int fl, int rsa_len);

        int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
           unsigned char *f, int fl);

        int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
           unsigned char *f, int fl, int rsa_len);

        int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
           unsigned char *f, int fl, unsigned char *p, int pl);

        int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
           unsigned char *f, int fl, int rsa_len, unsigned char *p, int pl);

        int RSA_padding_add_SSLv23(unsigned char *to, int tlen,
           unsigned char *f, int fl);

        int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
           unsigned char *f, int fl, int rsa_len);

        int RSA_padding_add_none(unsigned char *to, int tlen,
           unsigned char *f, int fl);

        int RSA_padding_check_none(unsigned char *to, int tlen,
           unsigned char *f, int fl, int rsa_len);


DESCRIPTION

       The RSA_padding_xxx_xxx() functions are called from the
       RSA encrypt, decrypt, sign and verify functions. Normally
       they should not be called from application programs.

       However, they can also be called directly to implement
       padding for other asymmetric ciphers.
       RSA_padding_add_PKCS1_OAEP() and
       RSA_padding_check_PKCS1_OAEP() may be used in an
       application combined with RSA_NO_PADDING in order to


       RSA_padding_add_xxx() encodes fl bytes from f so as to fit
       into tlen bytes and stores the result at to. An error
       occurs if fl does not meet the size requirements of the
       encoding method.

       The following encoding methods are implemented:

       PKCS1_type_1
           PKCS #1 v2.0 EMSA-PKCS1-v1_5 (PKCS #1 v1.5 block type
           1); used for signatures

       PKCS1_type_2
           PKCS #1 v2.0 EME-PKCS1-v1_5 (PKCS #1 v1.5 block type
           2)

       PKCS1_OAEP
           PKCS #1 v2.0 EME-OAEP

       SSLv23
           PKCS #1 EME-PKCS1-v1_5 with SSL-specific modification

       none
           simply copy the data

       The random number generator must be seeded prior to
       calling RSA_padding_add_xxx().

       RSA_padding_check_xxx() verifies that the fl bytes at f
       contain a valid encoding for a rsa_len byte RSA key in the
       respective encoding method and stores the recovered data
       of at most tlen bytes (for RSA_NO_PADDING: of size tlen)
       at to.

       For RSA_padding_xxx_OAEP(), p points to the encoding
       parameter of length pl. p may be NULL if pl is 0.


RETURN VALUES

       The RSA_padding_add_xxx() functions return 1 on success, 0
       on error.  The RSA_padding_check_xxx() functions return
       the length of the recovered data, -1 on error. Error codes
       can be obtained by calling ERR_get_error(3).


SEE ALSO

       RSA_public_encrypt(3), RSA_private_decrypt(3),
       RSA_sign(3), RSA_verify(3)


HISTORY

       RSA_padding_add_PKCS1_type_1(),
       RSA_padding_check_PKCS1_type_1(),
       RSA_padding_add_PKCS1_type_2(),
       RSA_padding_check_PKCS1_type_2(),
       RSA_padding_add_SSLv23(), RSA_padding_check_SSLv23(),

       appeared in SSLeay 0.9.0.

       RSA_padding_add_PKCS1_OAEP() and
       RSA_padding_check_PKCS1_OAEP() were added in OpenSSL
       0.9.2b.

       RSA_padding_add_PKCS1_OAEP, RSA_padding_check_PKCS1_OAEP,
       RSA_padding_add_SSLv23, RSA_padding_check_SSLv23,
       RSA_padding_add_none, RSA_padding_check_none - asymmetric
       encryption padding"


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