mirror of
https://github.com/openssl/openssl.git
synced 2024-12-03 05:41:46 +08:00
e4a1d02300
These functions would only handle provided methods, but there are cases where the caller just passes along a received method without knowing the underlying method tech, so might pass along a legacy method. We therefore need to have them handle this case as well so they don't cause any unnecessary surprises. Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/10845)
644 lines
21 KiB
Plaintext
644 lines
21 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
EVP_MD_fetch, EVP_MD_up_ref, EVP_MD_free,
|
|
EVP_MD_get_params, EVP_MD_gettable_params,
|
|
EVP_MD_CTX_new, EVP_MD_CTX_reset, EVP_MD_CTX_free, EVP_MD_CTX_copy,
|
|
EVP_MD_CTX_copy_ex, EVP_MD_CTX_ctrl,
|
|
EVP_MD_CTX_set_params, EVP_MD_CTX_get_params,
|
|
EVP_MD_settable_ctx_params, EVP_MD_gettable_ctx_params,
|
|
EVP_MD_CTX_settable_params, EVP_MD_CTX_gettable_params,
|
|
EVP_MD_CTX_set_flags, EVP_MD_CTX_clear_flags, EVP_MD_CTX_test_flags,
|
|
EVP_Digest, EVP_DigestInit_ex, EVP_DigestInit, EVP_DigestUpdate,
|
|
EVP_DigestFinal_ex, EVP_DigestFinalXOF, EVP_DigestFinal,
|
|
EVP_MD_is_a, EVP_MD_name, EVP_MD_number, EVP_MD_names_do_all, EVP_MD_provider,
|
|
EVP_MD_type, EVP_MD_pkey_type, EVP_MD_size, EVP_MD_block_size, EVP_MD_flags,
|
|
EVP_MD_CTX_name,
|
|
EVP_MD_CTX_md, EVP_MD_CTX_type, EVP_MD_CTX_size, EVP_MD_CTX_block_size,
|
|
EVP_MD_CTX_md_data, EVP_MD_CTX_update_fn, EVP_MD_CTX_set_update_fn,
|
|
EVP_md_null,
|
|
EVP_get_digestbyname, EVP_get_digestbynid, EVP_get_digestbyobj,
|
|
EVP_MD_CTX_pkey_ctx, EVP_MD_CTX_set_pkey_ctx,
|
|
EVP_MD_do_all_provided
|
|
- EVP digest routines
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/evp.h>
|
|
|
|
EVP_MD *EVP_MD_fetch(OPENSSL_CTX *ctx, const char *algorithm,
|
|
const char *properties);
|
|
int EVP_MD_up_ref(EVP_MD *md);
|
|
void EVP_MD_free(EVP_MD *md);
|
|
int EVP_MD_get_params(const EVP_MD *digest, OSSL_PARAM params[]);
|
|
const OSSL_PARAM *EVP_MD_gettable_params(const EVP_MD *digest);
|
|
EVP_MD_CTX *EVP_MD_CTX_new(void);
|
|
int EVP_MD_CTX_reset(EVP_MD_CTX *ctx);
|
|
void EVP_MD_CTX_free(EVP_MD_CTX *ctx);
|
|
void EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int cmd, int p1, void* p2);
|
|
int EVP_MD_CTX_get_params(EVP_MD_CTX *ctx, OSSL_PARAM params[]);
|
|
int EVP_MD_CTX_set_params(EVP_MD_CTX *ctx, const OSSL_PARAM params[]);
|
|
const OSSL_PARAM *EVP_MD_settable_ctx_params(const EVP_MD *md);
|
|
const OSSL_PARAM *EVP_MD_gettable_ctx_params(const EVP_MD *md);
|
|
const OSSL_PARAM *EVP_MD_CTX_settable_params(EVP_MD_CTX *ctx);
|
|
const OSSL_PARAM *EVP_MD_CTX_gettable_params(EVP_MD_CTX *ctx);
|
|
void EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags);
|
|
void EVP_MD_CTX_clear_flags(EVP_MD_CTX *ctx, int flags);
|
|
int EVP_MD_CTX_test_flags(const EVP_MD_CTX *ctx, int flags);
|
|
|
|
int EVP_Digest(const void *data, size_t count, unsigned char *md,
|
|
unsigned int *size, const EVP_MD *type, ENGINE *impl);
|
|
int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
|
|
int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
|
|
int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
|
|
int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, unsigned char *md, size_t len);
|
|
|
|
int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
|
|
|
|
int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
|
|
int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
|
|
|
|
int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
|
|
|
|
const char *EVP_MD_name(const EVP_MD *md);
|
|
int EVP_MD_number(const EVP_MD *md);
|
|
int EVP_MD_is_a(const EVP_MD *md, const char *name);
|
|
void EVP_MD_names_do_all(const EVP_MD *md,
|
|
void (*fn)(const char *name, void *data),
|
|
void *data);
|
|
const OSSL_PROVIDER *EVP_MD_provider(const EVP_MD *md);
|
|
int EVP_MD_type(const EVP_MD *md);
|
|
int EVP_MD_pkey_type(const EVP_MD *md);
|
|
int EVP_MD_size(const EVP_MD *md);
|
|
int EVP_MD_block_size(const EVP_MD *md);
|
|
unsigned long EVP_MD_flags(const EVP_MD *md);
|
|
|
|
const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
|
|
const char *EVP_MD_CTX_name(const EVP_MD_CTX *ctx);
|
|
int EVP_MD_CTX_size(const EVP_MD_CTX *ctx);
|
|
int EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx);
|
|
int EVP_MD_CTX_type(const EVP_MD_CTX *ctx);
|
|
void *EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx);
|
|
int (*EVP_MD_CTX_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
|
|
const void *data, size_t count);
|
|
void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
|
|
int (*update)(EVP_MD_CTX *ctx,
|
|
const void *data, size_t count));
|
|
|
|
const EVP_MD *EVP_md_null(void);
|
|
|
|
const EVP_MD *EVP_get_digestbyname(const char *name);
|
|
const EVP_MD *EVP_get_digestbynid(int type);
|
|
const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
|
|
|
|
EVP_PKEY_CTX *EVP_MD_CTX_pkey_ctx(const EVP_MD_CTX *ctx);
|
|
void EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx);
|
|
|
|
void EVP_MD_do_all_provided(OPENSSL_CTX *libctx,
|
|
void (*fn)(EVP_MD *mac, void *arg),
|
|
void *arg);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The EVP digest routines are a high level interface to message digests,
|
|
and should be used instead of the digest-specific functions.
|
|
|
|
The B<EVP_MD> type is a structure for digest method implementation.
|
|
|
|
=over 4
|
|
|
|
=item EVP_MD_fetch()
|
|
|
|
Fetches the digest implementation for the given B<algorithm> from any
|
|
provider offering it, within the criteria given by the B<properties>.
|
|
See L<provider(7)/Fetching algorithms> for further information.
|
|
|
|
The returned value must eventually be freed with EVP_MD_free().
|
|
|
|
Fetched B<EVP_MD> structures are reference counted.
|
|
|
|
=item EVP_MD_up_ref()
|
|
|
|
Increments the reference count for an B<EVP_MD> structure.
|
|
|
|
=item EVP_MD_free()
|
|
|
|
Decrements the reference count for the fetched B<EVP_MD> structure.
|
|
If the reference count drops to 0 then the structure is freed.
|
|
|
|
=item EVP_MD_CTX_new()
|
|
|
|
Allocates and returns a digest context.
|
|
|
|
=item EVP_MD_CTX_reset()
|
|
|
|
Resets the digest context B<ctx>. This can be used to reuse an already
|
|
existing context.
|
|
|
|
=item EVP_MD_CTX_free()
|
|
|
|
Cleans up digest context B<ctx> and frees up the space allocated to it.
|
|
|
|
=item EVP_MD_CTX_ctrl()
|
|
|
|
This is a legacy method. EVP_MD_CTX_set_params() and EVP_MD_CTX_get_params()
|
|
is the mechanism that should be used to set and get parameters that are used by
|
|
providers.
|
|
Performs digest-specific control actions on context B<ctx>. The control command
|
|
is indicated in B<cmd> and any additional arguments in B<p1> and B<p2>.
|
|
EVP_MD_CTX_ctrl() must be called after EVP_DigestInit_ex(). Other restrictions
|
|
may apply depending on the control type and digest implementation.
|
|
See L</CONTROLS> below for more information.
|
|
|
|
=item EVP_MD_get_params()
|
|
|
|
Retrieves the requested list of B<params> from a MD B<md>.
|
|
See L</PARAMETERS> below for more information.
|
|
|
|
=item EVP_MD_CTX_get_params()
|
|
|
|
Retrieves the requested list of B<params> from a MD context B<ctx>.
|
|
See L</PARAMETERS> below for more information.
|
|
|
|
=item EVP_MD_CTX_set_params()
|
|
|
|
Sets the list of B<params> into a MD context B<ctx>.
|
|
See L</PARAMETERS> below for more information.
|
|
|
|
=item EVP_MD_gettable_params(), EVP_MD_gettable_ctx_params(),
|
|
EVP_MD_settable_ctx_params(), EVP_MD_CTX_gettable_params(),
|
|
EVP_MD_CTX_settable_params()
|
|
|
|
Get a B<OSSL_PARAM> array that describes the retrievable and settable
|
|
parameters. EVP_MD_gettable_params() returns parameters that can be used with
|
|
EVP_MD_get_params(). EVP_MD_gettable_ctx_params() and
|
|
EVP_MD_CTX_gettable_params() return parameters that can be used with
|
|
EVP_MD_CTX_get_params(). EVP_MD_settable_ctx_params() and
|
|
EVP_MD_CTX_settable_params() return parameters that can be used with
|
|
EVP_MD_CTX_set_params().
|
|
See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
|
|
|
|
=item EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags(), EVP_MD_CTX_test_flags()
|
|
|
|
Sets, clears and tests B<ctx> flags. See L</FLAGS> below for more information.
|
|
|
|
=item EVP_Digest()
|
|
|
|
A wrapper around the Digest Init_ex, Update and Final_ex functions.
|
|
Hashes B<count> bytes of data at B<data> using a digest B<type> from ENGINE
|
|
B<impl>. The digest value is placed in B<md> and its length is written at B<size>
|
|
if the pointer is not NULL. At most B<EVP_MAX_MD_SIZE> bytes will be written.
|
|
If B<impl> is NULL the default implementation of digest B<type> is used.
|
|
|
|
=item EVP_DigestInit_ex()
|
|
|
|
Sets up digest context B<ctx> to use a digest B<type>.
|
|
B<type> is typically supplied by a function such as EVP_sha1(), or a
|
|
value explicitly fetched with EVP_MD_fetch().
|
|
|
|
If B<impl> is non-NULL, its implementation of the digest B<type> is used if
|
|
there is one, and if not, the default implementation is used.
|
|
|
|
=item EVP_DigestUpdate()
|
|
|
|
Hashes B<cnt> bytes of data at B<d> into the digest context B<ctx>. This
|
|
function can be called several times on the same B<ctx> to hash additional
|
|
data.
|
|
|
|
=item EVP_DigestFinal_ex()
|
|
|
|
Retrieves the digest value from B<ctx> and places it in B<md>. If the B<s>
|
|
parameter is not NULL then the number of bytes of data written (i.e. the
|
|
length of the digest) will be written to the integer at B<s>, at most
|
|
B<EVP_MAX_MD_SIZE> bytes will be written. After calling EVP_DigestFinal_ex()
|
|
no additional calls to EVP_DigestUpdate() can be made, but
|
|
EVP_DigestInit_ex() can be called to initialize a new digest operation.
|
|
|
|
=item EVP_DigestFinalXOF()
|
|
|
|
Interfaces to extendable-output functions, XOFs, such as SHAKE128 and SHAKE256.
|
|
It retrieves the digest value from B<ctx> and places it in B<len>-sized <B>md.
|
|
After calling this function no additional calls to EVP_DigestUpdate() can be
|
|
made, but EVP_DigestInit_ex() can be called to initialize a new operation.
|
|
|
|
=item EVP_MD_CTX_copy_ex()
|
|
|
|
Can be used to copy the message digest state from B<in> to B<out>. This is
|
|
useful if large amounts of data are to be hashed which only differ in the last
|
|
few bytes.
|
|
|
|
=item EVP_DigestInit()
|
|
|
|
Behaves in the same way as EVP_DigestInit_ex() except it always uses the
|
|
default digest implementation and calls EVP_MD_CTX_reset().
|
|
|
|
=item EVP_DigestFinal()
|
|
|
|
Similar to EVP_DigestFinal_ex() except the digest context B<ctx> is
|
|
automatically cleaned up.
|
|
|
|
=item EVP_MD_CTX_copy()
|
|
|
|
Similar to EVP_MD_CTX_copy_ex() except the destination B<out> does not have to
|
|
be initialized.
|
|
|
|
=item EVP_MD_is_a()
|
|
|
|
Returns 1 if I<md> is an implementation of an algorithm that's
|
|
identifiable with I<name>, otherwise 0.
|
|
|
|
If I<md> is a legacy digest (it's the return value from the likes of
|
|
EVP_sha256() rather than the result of an EVP_MD_fetch()), only cipher
|
|
names registered with the default library context (see
|
|
L<OPENSSL_CTX(3)>) will be considered.
|
|
|
|
=item EVP_MD_number()
|
|
|
|
Returns the internal dynamic number assigned to the I<md>. This is
|
|
only useful with fetched B<EVP_MD>s.
|
|
|
|
=item EVP_MD_name(),
|
|
EVP_MD_CTX_name()
|
|
|
|
Return the name of the given message digest. For fetched message
|
|
digests with multiple names, only one of them is returned; it's
|
|
recommended to use EVP_MD_names_do_all() instead.
|
|
|
|
=item EVP_MD_names_do_all()
|
|
|
|
Traverses all names for the I<md>, and calls I<fn> with each name and
|
|
I<data>. This is only useful with fetched B<EVP_MD>s.
|
|
|
|
=item EVP_MD_provider()
|
|
|
|
Returns an B<OSSL_PROVIDER> pointer to the provider that implements the given
|
|
B<EVP_MD>.
|
|
|
|
=item EVP_MD_size(),
|
|
EVP_MD_CTX_size()
|
|
|
|
Return the size of the message digest when passed an B<EVP_MD> or an
|
|
B<EVP_MD_CTX> structure, i.e. the size of the hash.
|
|
|
|
=item EVP_MD_block_size(),
|
|
EVP_MD_CTX_block_size()
|
|
|
|
Return the block size of the message digest when passed an B<EVP_MD> or an
|
|
B<EVP_MD_CTX> structure.
|
|
|
|
=item EVP_MD_type(),
|
|
EVP_MD_CTX_type()
|
|
|
|
Return the NID of the OBJECT IDENTIFIER representing the given message digest
|
|
when passed an B<EVP_MD> structure. For example, C<EVP_MD_type(EVP_sha1())>
|
|
returns B<NID_sha1>. This function is normally used when setting ASN1 OIDs.
|
|
|
|
=item EVP_MD_CTX_md_data()
|
|
|
|
Return the digest method private data for the passed B<EVP_MD_CTX>.
|
|
The space is allocated by OpenSSL and has the size originally set with
|
|
EVP_MD_meth_set_app_datasize().
|
|
|
|
=item EVP_MD_CTX_md()
|
|
|
|
Returns the B<EVP_MD> structure corresponding to the passed B<EVP_MD_CTX>. This
|
|
will be the same B<EVP_MD> object originally passed to EVP_DigestInit_ex() (or
|
|
other similar function) when the EVP_MD_CTX was first initialised. Note that
|
|
where explicit fetch is in use (see L<EVP_MD_fetch(3)>) the value returned from
|
|
this function will not have its reference count incremented and therefore it
|
|
should not be used after the EVP_MD_CTX is freed.
|
|
|
|
=item EVP_MD_CTX_set_update_fn()
|
|
|
|
Sets the update function for B<ctx> to B<update>.
|
|
This is the function that is called by EVP_DigestUpdate. If not set, the
|
|
update function from the B<EVP_MD> type specified at initialization is used.
|
|
|
|
=item EVP_MD_CTX_update_fn()
|
|
|
|
Returns the update function for B<ctx>.
|
|
|
|
=item EVP_MD_flags()
|
|
|
|
Returns the B<md> flags. Note that these are different from the B<EVP_MD_CTX>
|
|
ones. See L<EVP_MD_meth_set_flags(3)> for more information.
|
|
|
|
=item EVP_MD_pkey_type()
|
|
|
|
Returns the NID of the public key signing algorithm associated with this
|
|
digest. For example EVP_sha1() is associated with RSA so this will return
|
|
B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms are no
|
|
longer linked this function is only retained for compatibility reasons.
|
|
|
|
=item EVP_md_null()
|
|
|
|
A "null" message digest that does nothing: i.e. the hash it returns is of zero
|
|
length.
|
|
|
|
=item EVP_get_digestbyname(),
|
|
EVP_get_digestbynid(),
|
|
EVP_get_digestbyobj()
|
|
|
|
Returns an B<EVP_MD> structure when passed a digest name, a digest B<NID> or an
|
|
B<ASN1_OBJECT> structure respectively.
|
|
|
|
=item EVP_MD_CTX_pkey_ctx()
|
|
|
|
Returns the B<EVP_PKEY_CTX> assigned to B<ctx>. The returned pointer should not
|
|
be freed by the caller.
|
|
|
|
=item EVP_MD_CTX_set_pkey_ctx()
|
|
|
|
Assigns an B<EVP_PKEY_CTX> to B<EVP_MD_CTX>. This is usually used to provide
|
|
a customized B<EVP_PKEY_CTX> to L<EVP_DigestSignInit(3)> or
|
|
L<EVP_DigestVerifyInit(3)>. The B<pctx> passed to this function should be freed
|
|
by the caller. A NULL B<pctx> pointer is also allowed to clear the B<EVP_PKEY_CTX>
|
|
assigned to B<ctx>. In such case, freeing the cleared B<EVP_PKEY_CTX> or not
|
|
depends on how the B<EVP_PKEY_CTX> is created.
|
|
|
|
=item EVP_MD_do_all_provided()
|
|
|
|
Traverses all messages digests implemented by all activated providers
|
|
in the given library context I<libctx>, and for each of the implementations,
|
|
calls the given function I<fn> with the implementation method and the given
|
|
I<arg> as argument.
|
|
|
|
=back
|
|
|
|
=head1 PARAMETERS
|
|
|
|
See L<OSSL_PARAM(3)> for information about passing parameters.
|
|
|
|
EVP_MD_CTX_set_params() can be used with the following OSSL_PARAM keys:
|
|
|
|
=over 4
|
|
|
|
=item "xoflen" (B<OSSL_PARAM_DIGEST_KEY_XOFLEN>) <unsigned integer>
|
|
|
|
Sets the digest length for extendable output functions.
|
|
It is used by the SHAKE algorithm and should not exceed what can be given
|
|
using a B<size_t>.
|
|
|
|
=item "pad_type" (B<OSSL_PARAM_DIGEST_KEY_PAD_TYPE>) <integer>
|
|
|
|
Sets the pad type.
|
|
It is used by the MDC2 algorithm.
|
|
|
|
=back
|
|
|
|
EVP_MD_CTX_get_params() can be used with the following OSSL_PARAM keys:
|
|
|
|
=over 4
|
|
|
|
=item "micalg" (B<OSSL_PARAM_DIGEST_KEY_MICALG>) <UTF8 string>.
|
|
|
|
Gets the digest Message Integrity Check algorithm string. This is used when
|
|
creating S/MIME multipart/signed messages, as specified in RFC 3851.
|
|
It may be used by external engines or providers.
|
|
|
|
=back
|
|
|
|
=head1 CONTROLS
|
|
|
|
EVP_MD_CTX_ctrl() can be used to send the following standard controls:
|
|
|
|
=over 4
|
|
|
|
=item EVP_MD_CTRL_MICALG
|
|
|
|
Gets the digest Message Integrity Check algorithm string. This is used when
|
|
creating S/MIME multipart/signed messages, as specified in RFC 3851.
|
|
The string value is written to B<p2>.
|
|
|
|
=item EVP_MD_CTRL_XOF_LEN
|
|
|
|
This control sets the digest length for extendable output functions to B<p1>.
|
|
Sending this control directly should not be necessary, the use of
|
|
C<EVP_DigestFinalXOF()> is preferred.
|
|
Currently used by SHAKE.
|
|
|
|
=back
|
|
|
|
=head1 FLAGS
|
|
|
|
EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags() and EVP_MD_CTX_test_flags()
|
|
can be used the manipulate and test these B<EVP_MD_CTX> flags:
|
|
|
|
=over 4
|
|
|
|
=item EVP_MD_CTX_FLAG_ONESHOT
|
|
|
|
This flag instructs the digest to optimize for one update only, if possible.
|
|
|
|
=for comment EVP_MD_CTX_FLAG_CLEANED is internal, don't mention it
|
|
|
|
=for comment EVP_MD_CTX_FLAG_REUSE is internal, don't mention it
|
|
|
|
=for comment We currently avoid documenting flags that are only bit holder:
|
|
EVP_MD_CTX_FLAG_NON_FIPS_ALLOW, EVP_MD_CTX_FLAGS_PAD_*
|
|
|
|
=item EVP_MD_CTX_FLAG_NO_INIT
|
|
|
|
This flag instructs EVP_DigestInit() and similar not to initialise the
|
|
implementation specific data.
|
|
|
|
=item EVP_MD_CTX_FLAG_FINALISE
|
|
|
|
Some functions such as EVP_DigestSign only finalise copies of internal
|
|
contexts so additional data can be included after the finalisation call.
|
|
This is inefficient if this functionality is not required, and can be
|
|
disabled with this flag.
|
|
|
|
=back
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
=over 4
|
|
|
|
=item EVP_MD_fetch()
|
|
|
|
Returns a pointer to a B<EVP_MD> for success or NULL for failure.
|
|
|
|
=item EVP_MD_up_ref()
|
|
|
|
Returns 1 for success or 0 for failure.
|
|
|
|
=item EVP_DigestInit_ex(),
|
|
EVP_DigestUpdate(),
|
|
EVP_DigestFinal_ex()
|
|
|
|
Returns 1 for
|
|
success and 0 for failure.
|
|
|
|
=item EVP_MD_CTX_ctrl()
|
|
|
|
Returns 1 if successful or 0 for failure.
|
|
|
|
=item EVP_MD_CTX_set_params(),
|
|
EVP_MD_CTX_get_params()
|
|
|
|
Returns 1 if successful or 0 for failure.
|
|
|
|
=item EVP_MD_CTX_settable_params(),
|
|
EVP_MD_CTX_gettable_params()
|
|
|
|
Return an array of constant B<OSSL_PARAM>s, or NULL if there is none
|
|
to get.
|
|
|
|
=item EVP_MD_CTX_copy_ex()
|
|
|
|
Returns 1 if successful or 0 for failure.
|
|
|
|
=item EVP_MD_type(),
|
|
EVP_MD_pkey_type()
|
|
|
|
Returns the NID of the corresponding OBJECT IDENTIFIER or NID_undef if none
|
|
exists.
|
|
|
|
=item EVP_MD_size(),
|
|
EVP_MD_block_size(),
|
|
EVP_MD_CTX_size(),
|
|
EVP_MD_CTX_block_size()
|
|
|
|
Returns the digest or block size in bytes.
|
|
|
|
=item EVP_md_null()
|
|
|
|
Returns a pointer to the B<EVP_MD> structure of the "null" message digest.
|
|
|
|
=item EVP_get_digestbyname(),
|
|
EVP_get_digestbynid(),
|
|
EVP_get_digestbyobj()
|
|
|
|
Returns either an B<EVP_MD> structure or NULL if an error occurs.
|
|
|
|
=item EVP_MD_CTX_set_pkey_ctx()
|
|
|
|
This function has no return value.
|
|
|
|
=back
|
|
|
|
=head1 NOTES
|
|
|
|
The B<EVP> interface to message digests should almost always be used in
|
|
preference to the low level interfaces. This is because the code then becomes
|
|
transparent to the digest used and much more flexible.
|
|
|
|
New applications should use the SHA-2 (such as L<EVP_sha256(3)>) or the SHA-3
|
|
digest algorithms (such as L<EVP_sha3_512(3)>). The other digest algorithms
|
|
are still in common use.
|
|
|
|
For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
|
|
set to NULL to use the default digest implementation.
|
|
|
|
The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
|
|
obsolete but are retained to maintain compatibility with existing code. New
|
|
applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
|
|
EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
|
|
instead of initializing and cleaning it up on each call and allow non default
|
|
implementations of digests to be specified.
|
|
|
|
If digest contexts are not cleaned up after use,
|
|
memory leaks will occur.
|
|
|
|
EVP_MD_CTX_name(), EVP_MD_CTX_size(), EVP_MD_CTX_block_size(),
|
|
EVP_MD_CTX_type(), EVP_get_digestbynid() and EVP_get_digestbyobj() are defined
|
|
as macros.
|
|
|
|
EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
|
|
or control.
|
|
|
|
=head1 EXAMPLES
|
|
|
|
This example digests the data "Test Message\n" and "Hello World\n", using the
|
|
digest name passed on the command line.
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <openssl/evp.h>
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
EVP_MD_CTX *mdctx;
|
|
const EVP_MD *md;
|
|
char mess1[] = "Test Message\n";
|
|
char mess2[] = "Hello World\n";
|
|
unsigned char md_value[EVP_MAX_MD_SIZE];
|
|
unsigned int md_len, i;
|
|
|
|
if (argv[1] == NULL) {
|
|
printf("Usage: mdtest digestname\n");
|
|
exit(1);
|
|
}
|
|
|
|
md = EVP_get_digestbyname(argv[1]);
|
|
if (md == NULL) {
|
|
printf("Unknown message digest %s\n", argv[1]);
|
|
exit(1);
|
|
}
|
|
|
|
mdctx = EVP_MD_CTX_new();
|
|
EVP_DigestInit_ex(mdctx, md, NULL);
|
|
EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
|
|
EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
|
|
EVP_DigestFinal_ex(mdctx, md_value, &md_len);
|
|
EVP_MD_CTX_free(mdctx);
|
|
|
|
printf("Digest is: ");
|
|
for (i = 0; i < md_len; i++)
|
|
printf("%02x", md_value[i]);
|
|
printf("\n");
|
|
|
|
exit(0);
|
|
}
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<EVP_MD_meth_new(3)>,
|
|
L<openssl-dgst(1)>,
|
|
L<evp(7)>,
|
|
L<OSSL_PROVIDER(3)>,
|
|
L<OSSL_PARAM(3)>
|
|
|
|
The full list of digest algorithms are provided below.
|
|
|
|
L<EVP_blake2b512(3)>,
|
|
L<EVP_md2(3)>,
|
|
L<EVP_md4(3)>,
|
|
L<EVP_md5(3)>,
|
|
L<EVP_mdc2(3)>,
|
|
L<EVP_ripemd160(3)>,
|
|
L<EVP_sha1(3)>,
|
|
L<EVP_sha224(3)>,
|
|
L<EVP_sha3_224(3)>,
|
|
L<EVP_sm3(3)>,
|
|
L<EVP_whirlpool(3)>
|
|
L<provider(7)/Fetching algorithms>
|
|
|
|
=head1 HISTORY
|
|
|
|
The EVP_MD_CTX_create() and EVP_MD_CTX_destroy() functions were renamed to
|
|
EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.0, respectively.
|
|
|
|
The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
|
|
later, so now EVP_sha1() can be used with RSA and DSA.
|
|
|
|
The EVP_dss1() function was removed in OpenSSL 1.1.0.
|
|
|
|
The EVP_MD_CTX_set_pkey_ctx() function was added in 1.1.1.
|
|
|
|
The EVP_MD_fetch(), EVP_MD_free(), EVP_MD_up_ref(), EVP_MD_CTX_set_params()
|
|
and EVP_MD_CTX_get_params() functions were added in 3.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
Licensed under the Apache License 2.0 (the "License"). You may not use
|
|
this file except in compliance with the License. You can obtain a copy
|
|
in the file LICENSE in the source distribution or at
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|