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Various parts of the RSA documentation were inaccurate and out of date and

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this fixes those that I'm currently aware of. In particular, the ENGINE
interference in the RSA API has hopefully been clarified. This still needs
to be done for other areas of the API ...
This commit is contained in:
Geoff Thorpe 2002-08-04 21:08:36 +00:00
parent 3f90e45079
commit ac120e20e3
3 changed files with 101 additions and 51 deletions
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6
doc/crypto/RSA_new.pod
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@ -14,7 +14,8 @@ RSA_new, RSA_free - allocate and free RSA objects
=head1 DESCRIPTION
RSA_new() allocates and initializes an B<RSA> structure.
RSA_new() allocates and initializes an B<RSA> structure. It is equivalent to
calling RSA_new_method(NULL).
RSA_free() frees the B<RSA> structure and its components. The key is
erased before the memory is returned to the system.
@ -29,7 +30,8 @@ RSA_free() returns no value.
=head1 SEE ALSO
L<err(3)|err(3)>, L<rsa(3)|rsa(3)>, L<RSA_generate_key(3)|RSA_generate_key(3)>
L<err(3)|err(3)>, L<rsa(3)|rsa(3)>, L<RSA_generate_key(3)|RSA_generate_key(3)>,
L<RSA_new_method(3)|RSA_new_method(3)>
=head1 HISTORY

115
doc/crypto/RSA_set_method.pod
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@ -11,52 +11,64 @@ RSA_null_method, RSA_flags, RSA_new_method - select RSA method
#include <openssl/rsa.h>
#include <openssl/engine.h>
void RSA_set_default_openssl_method(RSA_METHOD *meth);
void RSA_set_default_method(const RSA_METHOD *meth);
RSA_METHOD *RSA_get_default_openssl_method(void);
RSA_METHOD *RSA_get_default_method(void);
int RSA_set_method(RSA *rsa, ENGINE *engine);
int RSA_set_method(RSA *rsa, const RSA_METHOD *meth);
RSA_METHOD *RSA_get_method(RSA *rsa);
RSA_METHOD *RSA_get_method(const RSA *rsa);
RSA_METHOD *RSA_PKCS1_SSLeay(void);
RSA_METHOD *RSA_null_method(void);
int RSA_flags(RSA *rsa);
int RSA_flags(const RSA *rsa);
RSA *RSA_new_method(ENGINE *engine);
=head1 DESCRIPTION
An B<RSA_METHOD> specifies the functions that OpenSSL uses for RSA
operations. By modifying the method, alternative implementations
such as hardware accelerators may be used.
operations. By modifying the method, alternative implementations such as
hardware accelerators may be used. IMPORTANT: See the NOTES section for
important information about how these RSA API functions are affected by the
use of B<ENGINE> API calls.
Initially, the default is to use the OpenSSL internal implementation.
RSA_PKCS1_SSLeay() returns a pointer to that method.
Initially, the default RSA_METHOD is the OpenSSL internal implementation,
as returned by RSA_PKCS1_SSLeay().
RSA_set_default_openssl_method() makes B<meth> the default method for all B<RSA>
structures created later. B<NB:> This is true only whilst the default engine
for RSA operations remains as "openssl". ENGINEs provide an
encapsulation for implementations of one or more algorithms at a time, and all
the RSA functions mentioned here operate within the scope of the default
"openssl" engine.
RSA_set_default_method() makes B<meth> the default method for all <RSA>
structures created later. B<NB>: This is true only whilst no ENGINE has
been set as a default for RSA, so this function is no longer recommended.
RSA_get_default_openssl_method() returns a pointer to the current default
method for the "openssl" engine.
RSA_get_default_method() returns a pointer to the current default
RSA_METHOD. However, the meaningfulness of this result is dependant on
whether the ENGINE API is being used, so this function is no longer
recommended.
RSA_set_method() selects B<engine> for all operations using the key
B<rsa>.
RSA_set_method() selects B<meth> to perform all operations using the key
B<rsa>. This will replace the RSA_METHOD used by the RSA key and if the
previous method was supplied by an ENGINE, the handle to that ENGINE will
be released during the change. It is possible to have RSA keys that only
work with certain RSA_METHOD implementations (eg. from an ENGINE module
that supports embedded hardware-protected keys), and in such cases
attempting to change the RSA_METHOD for the key can have unexpected
results.
RSA_get_method() returns a pointer to the RSA_METHOD from the currently
selected ENGINE for B<rsa>.
RSA_get_method() returns a pointer to the RSA_METHOD being used by B<rsa>.
This method may or may not be supplied by an ENGINE implementation, but if
it is, the return value can only be guaranteed to be valid as long as the
RSA key itself is valid and does not have its implementation changed by
RSA_set_method().
RSA_flags() returns the B<flags> that are set for B<rsa>'s current method.
RSA_flags() returns the B<flags> that are set for B<rsa>'s current
RSA_METHOD. See the BUGS section.
RSA_new_method() allocates and initializes an RSA structure so that
B<engine> will be used for the RSA operations. If B<engine> is NULL,
the default engine for RSA operations is used.
B<engine> will be used for the RSA operations. If B<engine> is NULL, the
default ENGINE for RSA operations is used, and if no default ENGINE is set,
the RSA_METHOD controlled by RSA_set_default_method() is used.
=head1 THE RSA_METHOD STRUCTURE
@ -121,22 +133,45 @@ the default engine for RSA operations is used.
=head1 RETURN VALUES
RSA_PKCS1_SSLeay(), RSA_PKCS1_null_method(), RSA_get_default_openssl_method()
RSA_PKCS1_SSLeay(), RSA_PKCS1_null_method(), RSA_get_default_method()
and RSA_get_method() return pointers to the respective RSA_METHODs.
RSA_set_default_openssl_method() returns no value.
RSA_set_default_method() returns no value.
RSA_set_method() selects B<engine> as the engine that will be responsible for
all operations using the structure B<rsa>. If this function completes successfully,
then the B<rsa> structure will have its own functional reference of B<engine>, so
the caller should remember to free their own reference to B<engine> when they are
finished with it. NB: An ENGINE's RSA_METHOD can be retrieved (or set) by
ENGINE_get_RSA() or ENGINE_set_RSA().
RSA_set_method() returns a pointer to the old RSA_METHOD implementation
that was replaced. However, this return value should probably be ignored
because if it was supplied by an ENGINE, the pointer could be invalidated
at any time if the ENGINE is unloaded (in fact it could be unloaded as a
result of the RSA_set_method() function releasing its handle to the
ENGINE). For this reason, the return type may be replaced with a B<void>
declaration in a future release.
RSA_new_method() returns NULL and sets an error code that can be
obtained by L<ERR_get_error(3)|ERR_get_error(3)> if the allocation fails. Otherwise
RSA_new_method() returns NULL and sets an error code that can be obtained
by L<ERR_get_error(3)|ERR_get_error(3)> if the allocation fails. Otherwise
it returns a pointer to the newly allocated structure.
=head1 NOTES
As of version 0.9.7, RSA_METHOD implementations are grouped together with
other algorithmic APIs (eg. DSA_METHOD, EVP_CIPHER, etc) into B<ENGINE>
modules. If a default ENGINE is specified for RSA functionality using an
ENGINE API function, that will override any RSA defaults set using the RSA
API (ie. RSA_set_default_method()). For this reason, the ENGINE API is the
recommended way to control default implementations for use in RSA and other
cryptographic algorithms.
=head1 BUGS
The behaviour of RSA_flags() is a mis-feature that is left as-is for now
to avoid creating compatibility problems. RSA functionality, such as the
encryption functions, are controlled by the B<flags> value in the RSA key
itself, not by the B<flags> value in the RSA_METHOD attached to the RSA key
(which is what this function returns). If the flags element of an RSA key
is changed, the changes will be honoured by RSA functionality but will not
be reflected in the return value of the RSA_flags() function - in effect
RSA_flags() behaves more like an RSA_default_flags() function (which does
not currently exist).
=head1 SEE ALSO
L<rsa(3)|rsa(3)>, L<RSA_new(3)|RSA_new(3)>
@ -149,8 +184,14 @@ well as the rsa_sign and rsa_verify components of RSA_METHOD were
added in OpenSSL 0.9.4.
RSA_set_default_openssl_method() and RSA_get_default_openssl_method()
replaced RSA_set_default_method() and RSA_get_default_method() respectively,
and RSA_set_method() and RSA_new_method() were altered to use B<ENGINE>s
rather than B<RSA_METHOD>s during development of OpenSSL 0.9.6.
replaced RSA_set_default_method() and RSA_get_default_method()
respectively, and RSA_set_method() and RSA_new_method() were altered to use
B<ENGINE>s rather than B<RSA_METHOD>s during development of the engine
version of OpenSSL 0.9.6. For 0.9.7, the handling of defaults in the ENGINE
API was restructured so that this change was reversed, and behaviour of the
other functions resembled more closely the previous behaviour. The
behaviour of defaults in the ENGINE API now transparently overrides the
behaviour of defaults in the RSA API without requiring changing these
function prototypes.
=cut

31
doc/crypto/rsa.pod
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@ -16,13 +16,17 @@ rsa - RSA public key cryptosystem
unsigned char *to, RSA *rsa, int padding);
int RSA_private_decrypt(int flen, unsigned char *from,
unsigned char *to, RSA *rsa, int padding);
int RSA_private_encrypt(int flen, unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
int RSA_public_decrypt(int flen, unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
int RSA_sign(int type, unsigned char *m, unsigned int m_len,
unsigned char *sigret, unsigned int *siglen, RSA *rsa);
int RSA_verify(int type, unsigned char *m, unsigned int m_len,
unsigned char *sigbuf, unsigned int siglen, RSA *rsa);
int RSA_size(RSA *rsa);
int RSA_size(const RSA *rsa);
RSA *RSA_generate_key(int num, unsigned long e,
void (*callback)(int,int,void *), void *cb_arg);
@ -32,13 +36,13 @@ rsa - RSA public key cryptosystem
int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
void RSA_blinding_off(RSA *rsa);
void RSA_set_default_openssl_method(RSA_METHOD *meth);
RSA_METHOD *RSA_get_default_openssl_method(void);
int RSA_set_method(RSA *rsa, ENGINE *engine);
RSA_METHOD *RSA_get_method(RSA *rsa);
void RSA_set_default_method(const RSA_METHOD *meth);
const RSA_METHOD *RSA_get_default_method(void);
int RSA_set_method(RSA *rsa, const RSA_METHOD *meth);
const RSA_METHOD *RSA_get_method(const RSA *rsa);
RSA_METHOD *RSA_PKCS1_SSLeay(void);
RSA_METHOD *RSA_null_method(void);
int RSA_flags(RSA *rsa);
int RSA_flags(const RSA *rsa);
RSA *RSA_new_method(ENGINE *engine);
int RSA_print(BIO *bp, RSA *x, int offset);
@ -49,11 +53,6 @@ rsa - RSA public key cryptosystem
int RSA_set_ex_data(RSA *r,int idx,char *arg);
char *RSA_get_ex_data(RSA *r, int idx);
int RSA_private_encrypt(int flen, unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
int RSA_public_decrypt(int flen, unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
int RSA_sign_ASN1_OCTET_STRING(int dummy, unsigned char *m,
unsigned int m_len, unsigned char *sigret, unsigned int *siglen,
RSA *rsa);
@ -90,6 +89,14 @@ B<p>, B<q>, B<dmp1>, B<dmq1> and B<iqmp> may be B<NULL> in private
keys, but the RSA operations are much faster when these values are
available.
Note that RSA keys may use non-standard B<RSA_METHOD> implementations,
either directly or by the use of B<ENGINE> modules. In some cases (eg. an
ENGINE providing support for hardware-embedded keys), these BIGNUM values
will not be used by the implementation or may be used for alternative data
storage. For this reason, applications should generally avoid using RSA
structure elements directly and instead use API functions to query or
modify keys.
=head1 CONFORMING TO
SSL, PKCS #1 v2.0
@ -101,7 +108,7 @@ RSA was covered by a US patent which expired in September 2000.
=head1 SEE ALSO
L<rsa(1)|rsa(1)>, L<bn(3)|bn(3)>, L<dsa(3)|dsa(3)>, L<dh(3)|dh(3)>,
L<rand(3)|rand(3)>, L<RSA_new(3)|RSA_new(3)>,
L<rand(3)|rand(3)>, L<engine(3)|engine(3)>, L<RSA_new(3)|RSA_new(3)>,
L<RSA_public_encrypt(3)|RSA_public_encrypt(3)>,
L<RSA_sign(3)|RSA_sign(3)>, L<RSA_size(3)|RSA_size(3)>,
L<RSA_generate_key(3)|RSA_generate_key(3)>,