RSA_padding_add_PKCS1_OAEP(3)

RSA_padding_add_PKCS1_type_1(3OpenSSRSA_padding_add_PKCS1_type_1(3)

NAME

     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 implement OAEP with

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RSA_padding_add_PKCS1_type_1(3OpenSSRSA_padding_add_PKCS1_type_1(3)

     an encoding parameter.

     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).

WARNING

     The RSA_padding_check_PKCS1_type_2() padding check leaks
     timing information which can potentially be used to mount a
     Bleichenbacher padding oracle attack. This is an inherent
     weakness in the PKCS #1 v1.5 padding design. Prefer
     PKCS1_OAEP padding. Otherwise it can be recommended to pass
     zero-padded f, so that fl equals to rsa_len, and if fixed by
     protocol, tlen being set to the expected length. In such
     case leakage would be minimal, it would take attacker's
     ability to observe memory access pattern with byte

1.0.2t               Last change: 2019-09-10                    2

RSA_padding_add_PKCS1_type_1(3OpenSSRSA_padding_add_PKCS1_type_1(3)

     granilarity as it occurs, post-factum timing analysis won't
     do.

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(), RSA_padding_add_none() and
     RSA_padding_check_none() appeared in SSLeay 0.9.0.

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

1.0.2t               Last change: 2019-09-10                    3