diff options
Diffstat (limited to 'doc/crypto/EVP_DigestInit.pod')
-rw-r--r-- | doc/crypto/EVP_DigestInit.pod | 47 |
1 files changed, 27 insertions, 20 deletions
diff --git a/doc/crypto/EVP_DigestInit.pod b/doc/crypto/EVP_DigestInit.pod index 337ffb7930..b21e1013b3 100644 --- a/doc/crypto/EVP_DigestInit.pod +++ b/doc/crypto/EVP_DigestInit.pod @@ -43,60 +43,60 @@ EVP_DigestInit, EVP_DigestUpdate, EVP_DigestFinal - EVP digest routines The EVP digest routines are a high level interface to message digests. -B<EVP_DigestInit()> initialises a digest context B<ctx> to use a digest +EVP_DigestInit() initialises a digest context B<ctx> to use a digest B<type>: this will typically be supplied by a function such as -B<EVP_sha1()>. +EVP_sha1(). -B<EVP_DigestUpdate()> hashes B<cnt> bytes of data at B<d> into the +EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the digest context B<ctx>. This funtion can be called several times on the same B<ctx> to hash additional data. -B<EVP_DigestFinal()> retrieves the digest value from B<ctx> and places +EVP_DigestFinal() 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 B<EVP_DigestFinal> no additional calls to B<EVP_DigestUpdate> -can be made, but B<EVP_DigestInit> can be called to initialiase a new +After calling EVP_DigestFinal() no additional calls to EVP_DigestUpdate() +can be made, but EVP_DigestInit() can be called to initialiase a new digest operation. -B<EVP_MD_CTX_copy> can be used to copy the message digest state from +EVP_MD_CTX_copy() 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. -B<EVP_MD_size> and B<EVP_MD_CTX_size> return the size of the message digest +EVP_MD_size() and 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. -B<EVP_MD_block_size> and B<EVP_MD_CTX_block_size> return the block size of the +EVP_MD_block_size() and 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. -B<EVP_MD_type> and B<EVP_MD_CTX_type> return the NID of the OBJECT IDENTIFIER +EVP_MD_type() and 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 B<EVP_MD_type(EVP_sha1())> returns B<NID_sha1>. This function is +For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is normally used when setting ASN1 OIDs. -B<EVP_MD_CTX_type> return the B<EVP_MD> structure corresponding to the passed +EVP_MD_CTX_type() returns the B<EVP_MD> structure corresponding to the passed B<EVP_MD_CTX>. -B<EVP_MD_pkey_type> returns the NID of the public key signing algorithm associated -with this digest. For example B<EVP_sha1()> is associated with RSA so this will +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>. This "link" between digests and signature algorithms may not be retained in future versions of OpenSSL. -B<EVP_md2>, B<EVP_md5>, B<EVP_sha>, B<EVP_sha1>, B<EVP_mdc2> and B<EVP_ripemd160> +EVP_md2(), EVP_md5(), EVP_sha(), EVP_sha1(), EVP_mdc2() and EVP_ripemd160() return B<EVP_MD> structures for the MD2, MD5, SHA, SHA1, MDC2 and RIPEMD160 digest algorithms respectively. The associated signature algorithm is RSA in each case. -B<EVP_dss> and B<EVP_dss1> return B<EVP_MD> structures for SHA and SHA1 digest +EVP_dss() and EVP_dss1() return B<EVP_MD> structures for SHA and SHA1 digest algorithms but using DSS (DSA) for the signature algorithm. -B<EVP_md_null> is a "null" message digest that does nothing: i.e. the hash it +EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it returns is of zero length. -B<EVP_get_digestbyname>, B<EVP_get_digestbynid> and B<EVP_get_digestbyobj> +EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj() return an B<EVP_MD> structure when passed a digest name, a digest NID or and ASN1_OBJECT structure respectively. The digest table must be initialised -using, for example, B<OpenSSL_add_all_digests()> for these functions to work. +using, for example, OpenSSL_add_all_digests() for these functions to work. =head1 RETURN VALUES @@ -178,7 +178,7 @@ internal digest operations will never fail some future hardware based operations might. The link between digests and signing algorithms results in a situation where -B<EVP_sha1()> must be used with RSA and B<EVP_dss1()> must be used with DSS +EVP_sha1() must be used with RSA and EVP_dss1() must be used with DSS even though they are identical digests. The size of an B<EVP_MD_CTX> structure is determined at compile time: this results @@ -186,6 +186,13 @@ in code that must be recompiled if the size of B<EVP_MD_CTX> increases. =head1 SEE ALSO +L<evp(3)|evp(3)>, L<hmac(3)|hmac(3)>, L<md2(3)|md2(3)>, +L<md5(3)|md5(3)>, L<mdc2(3)|mdc2(3)>, L<ripemd(3)|ripemd(3)>, +L<sha(3)|sha(3)> + =head1 HISTORY +EVP_DigestInit(), EVP_DigestUpdate() and EVP_DigestFinal() are +available in all versions of SSLeay and OpenSSL. + =cut |