Improved HKDF and TLS1-PRF documentation (f04abe7d) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP OpenSSL

doc/apps/pkeyutl.pod

+8 −5

Original line number	Diff line number	Diff line
		@@ -123,12 +123,15 @@ derive a shared secret using the peer key.

		=item B<-kdf algorithm>

		Use key derivation function B<algorithm>. Note: additional paramers
		will normally have to be set and the KDF output length for this to work.
		Use key derivation function B<algorithm>. The supported algorithms are
		at present B<TLS1-PRF> and B<HKDF>.
		Note: additional paramers and the KDF output length will normally have to be
		set for this to work. See L<EVP_PKEY_HKDF(3)> and L<EVP_PKEY_TLS1_PRF(3)>
		for the supported string parameters of each algorithm.

		=item B<-kdflen length>

		Set the ouput length for KDF.
		Set the output length for KDF.

		=item B<-pkeyopt opt:value>

		@@ -155,7 +158,6 @@ for all available algorithms.
		When used with the B<-engine> option, it specifies to also use
		engine B<id> for crypto operations.


		=back

		=head1 NOTES
		@@ -269,4 +271,5 @@ seed consisting of the single byte 0xFF.
		=head1 SEE ALSO

		L<genpkey(1)>, L<pkey(1)>, L<rsautl(1)>
		L<dgst(1)>, L<rsa(1)>, L<genrsa(1)>
		L<dgst(1)>, L<rsa(1)>, L<genrsa(1)>,
		L<EVP_PKEY_HKDF(3)>, L<EVP_PKEY_TLS1_PRF(3)>

doc/crypto/EVP_PKEY_HKDF.pod

+21 −5

Original line number	Diff line number	Diff line
		@@ -23,7 +23,7 @@ HMAC-based Extract-and-Expand key derivation algorithm

		=head1 DESCRIPTION

		The EVP_PKEY_HKDF alogorithm implements the HKDF key derivation function.
		The EVP_PKEY_HKDF algorithm implements the HKDF key derivation function.
		HKDF follows the "extract-then-expand" paradigm, where the KDF logically
		consists of two modules. The first stage takes the input keying material
		and "extracts" from it a fixed-length pseudorandom key K. The second stage
		@@ -42,6 +42,17 @@ EVP_PKEY_CTX_add1_hkdf_info() sets the info value to B<infolen> bytes of the
		buffer B<info>. If a value is already set, it is appended to the existing
		value.

		=head1 STRING CTRLS

		HKDF also supports string based control operations via
		L<EVP_PKEY_CTX_ctrl_str(3)>.
		The B<type> parameter "md" uses the supplied B<value> as the name of the digest
		algorithm to use.
		The B<type> parameters "salt", "key" and "info" use the supplied B<value>
		parameter as a B<seed>, B<key> or B<info> value.
		The names "hexsalt", "hexkey" and "hexinfo" are similar except they take a hex
		string which is converted to binary.

		=head1 NOTES

		All these functions are implemented as macros.
		@@ -56,9 +67,13 @@ an error occurs.
		The total length of the info buffer cannot exceed 1024 bytes in length: this
		should be more than enough for any normal use of HKDF.

		The output length of the KDF is specified by the length parameter in the
		EVP_PKEY_derive() function. Since the output length is variable, setting
		the buffer to B<NULL> is not meaningful for HKDF.
		The output length of the KDF is specified via the length parameter to the
		L<EVP_PKEY_derive(3)> function.
		Since the HKDF output length is variable, passing a B<NULL> buffer as a means
		to obtain the requisite length is not meaningful with HKDF.
		Instead, the caller must allocate a buffer of the desired length, and pass that
		buffer to L<EVP_PKEY_derive(3)> along with (a pointer initialized to) the
		desired length.

		Optimised versions of HKDF can be implemented in an ENGINE.

		@@ -98,6 +113,7 @@ RFC 5869
		=head1 SEE ALSO

		L<EVP_PKEY_CTX_new(3)>,
		L<EVP_PKEY_derive(3)>,
		L<EVP_PKEY_CTX_ctrl_str(3)>,
		L<EVP_PKEY_derive(3)>

		=cut

doc/crypto/EVP_PKEY_TLS1_PRF.pod

+8 −5

Original line number	Diff line number	Diff line
		@@ -36,10 +36,13 @@ If a seed is already set it is appended to the existing value.
		=head1 STRING CTRLS

		The TLS PRF also supports string based control operations using
		EVP_PKEY_CTX_ctrl_str(). The B<type> parameters "secret" and "seed" use
		the supplied B<value> parameter as a secret or seed value. The names
		"hexsecret" and "hexseed" are similar except they take a hex string which
		is converted to binary.
		L<EVP_PKEY_CTX_ctrl_str(3)>.
		The B<type> parameter "md" uses the supplied B<value> as the name of the digest
		algorithm to use.
		The B<type> parameters "secret" and "seed" use the supplied B<value> parameter
		as a secret or seed value.
		The names "hexsecret" and "hexseed" are similar except they take a hex string
		which is converted to binary.

		=head1 NOTES

		@@ -90,7 +93,7 @@ and seed value "seed":
		=head1 SEE ALSO

		L<EVP_PKEY_CTX_new(3)>,
		L<EVP_PKEY_CTX_ctrl(3)>,
		L<EVP_PKEY_CTX_ctrl_str(3)>,
		L<EVP_PKEY_derive(3)>

		=cut