Commit Graph

177 Commits

Author SHA1 Message Date
Gilles Peskine
99d0259987 Improve documentation the shared secret format for FFDH 2018-11-15 17:48:15 +01:00
Gilles Peskine
d171e78b46 Document the peer_key format for psa_key_agreement 2018-11-15 17:48:15 +01:00
Gilles Peskine
6c6a023f99 More tweaks on EC-related wording
Use m for the bit size of the field order, not q which is
traditionally the field order.

Correct and clarify the private key representation format as has been
done for the private key and ECDH shared secret formats.
2018-11-15 17:48:15 +01:00
Gilles Peskine
7b5b4a01a4 Correct description of the ECDH shared secret
The endianness actually depends on the curve type.

Correct the terminology around "curve size" and "order of the curve".
I tried to find a formulation that is comprehensible to programmers
who do not know the underlying mathematics, but nonetheless correct
and precise.

Use similar terminology in other places that were using "order of the
curve" to describe the bit size associated with the curve.
2018-11-14 21:17:16 +01:00
Gilles Peskine
f5f442a50c More accurate description of the shared secret for ECDH
Don't refer to the "curve size", call it the "size of the order of the
curve".
2018-11-14 21:17:16 +01:00
Gilles Peskine
211a436f2e Document that key agreement produces a maximum-capacity generator 2018-11-14 21:15:37 +01:00
Gilles Peskine
79dd6229e4 Clarify the format of the (EC)DH shared secret 2018-11-14 21:15:37 +01:00
Gilles Peskine
2607bca666 Give "DH" and "DHM" as alternative names
Be consistent about calling it just "Diffie-Hellman", except once
where I state that "Diffie-Hellman-Merkle" is an alternative name.
2018-11-14 21:15:37 +01:00
Gilles Peskine
01d718cee8 New API function: psa_key_agreement
Set up a generator from a key agreement.
2018-11-14 21:15:37 +01:00
Gilles Peskine
8feb3a886d Support key derivation with non-predefined capacity
psa_key_derivation requires the caller to specify a maximum capacity.
This commit adds a special value that indicates that the maximum
capacity should be the maximum supported by the algorithm. This is
currently meant only for selection algorithms used on the shared
secret produced by a key agreement.
2018-11-14 21:15:37 +01:00
Gilles Peskine
93098fd996 Key agreement: macros for finite-field Diffie-Hellman, ECDH
Declare macros to represent key agreement algorithms.
2018-11-14 21:15:37 +01:00
Gilles Peskine
e8f0e3dc3c New algorithm category: key selection
A key selection algorithm is similar to a key derivation algorithm in
that it takes a secret input and produces a secret output stream.
However, unlike key derivation algorithms, there is no expectation
that the input cannot be reconstructed from the output. Key selection
algorithms are exclusively meant to be used on the output of a key
agreement algorithm to select chunks of the shared secret.
2018-11-14 21:15:37 +01:00
Gilles Peskine
92587dbf2b Write missing bit of the documentation of psa_key_derivation 2018-11-14 21:15:37 +01:00
Gilles Peskine
f7933939b3 Expand the documentation of import/export formats
Clarify that the key type determines the syntax of the input.

Clarify the constraints on implementations that support extra import
formats.
2018-10-31 14:10:07 +01:00
Gilles Peskine
f76aa7789b Private EC key format: change to raw secret value (doc, import)
Change the import/export format of private elliptic curve keys from
RFC 5915 to the raw secret value. This commit updates the format
specification and the import code, but not the export code.
2018-10-31 14:10:06 +01:00
Gilles Peskine
e0e9c7c417 New macro PSA_ALG_FULL_LENGTH_MAC
Provide a documented way of constructing the full-length MAC algorithm
from a truncated version.
2018-10-17 18:30:47 +02:00
Gilles Peskine
6d72ff9e79 Document that the minimum truncated MAC length is implementation-defined 2018-10-17 13:54:47 +02:00
Gilles Peskine
e1f2d7d1ac Document and check the consistency of truncated MAC encodings
Add comments noting that the maximum length of a MAC must fit in
PSA_ALG_MAC_TRUNCATION_MASK. Add a unit test that verifies that the
maximum MAC size fits.
2018-10-17 13:54:47 +02:00
Gilles Peskine
3111981d94 Fix parameter name in Doxygen documentation 2018-10-08 14:45:35 +02:00
Gilles Peskine
70f46e17e8 New macro PSA_ALG_AEAD_WITH_DEFAULT_TAG_LENGTH
Useful to analyze algorithm values.
2018-10-08 14:45:35 +02:00
Gilles Peskine
23cc2ff9a8 Add support for non-default-tag-size AEAD (CCM and GCM) 2018-10-08 14:42:11 +02:00
Gilles Peskine
d911eb7915 Add support for truncated MAC algorithms 2018-10-08 14:42:11 +02:00
Gilles Peskine
159ebf3b8e
Merge pull request #142 from ARMmbed/psa-metadata_validation
Algorithm and key type encoding validation
2018-09-24 10:38:39 +02:00
Jaeden Amero
40363fe3f5
Merge pull request #139 from ARMmbed/psa-PSA_ALG-block_cipher_padding
Correct and simplify block-based cipher modes
2018-09-21 09:38:27 +01:00
Gilles Peskine
00709fafb8 Rename PSA_ALG_HMAC_HASH to PSA_ALG_HMAC_GET_HASH
Be consistent with other GET_HASH macros.
2018-09-20 12:00:21 +02:00
Gilles Peskine
9df2dc87ab Fix name of PSA_ALG_IS_BLOCK_CIPHER_MAC
The macro was used under the name PSA_ALG_IS_BLOCK_CIPHER_MAC but
defined as PSA_ALG_IS_CIPHER_MAC. That wouldn't have worked if we used
this macro (we currently don't but it may become useful).
2018-09-20 12:00:21 +02:00
Gilles Peskine
70ce2c6170 FFDHE groups are not elliptic curves
TLS now defines named curves in the "TLS Supported Groups registry",
but we're using the encoding only for elliptic curves, so don't
include values that aren't named curve.

While we're at it, upgrade the reference to the shiny new RFC 8422.
2018-09-20 12:00:21 +02:00
Gilles Peskine
583b55d97d Add PSA_KEY_TYPE_IS_DSA to go with PSA_KEY_TYPE_IS_RSA
Also move PSA_KEY_TYPE_IS_RSA to a more logical location.
2018-09-20 12:00:21 +02:00
Gilles Peskine
daea26f70f Correct and simplify block-based cipher modes
OFB and CFB are streaming modes. XTS is a not a cipher mode but it
doesn't use a separate padding step. This leaves only CBC as a block
cipher mode that needs a padding step.

Since CBC is the only mode that uses a separate padding step, and is
likely to remain the only mode in the future, encode the padding mode
directly in the algorithm constant, rather than building up an
algorithm value from a chaining mode and a padding mode. This greatly
simplifies the interface as well as some parts of the implementation.
2018-09-20 11:58:22 +02:00
itayzafrir
1861709e5c Add documentation describing behavior of not calling psa_crypto_init 2018-09-16 12:42:53 +03:00
itayzafrir
90d8c7a728 Ensure the module is initialized in key based functions 2018-09-16 12:15:47 +03:00
itayzafrir
0adf0fc31c Ensure the module is initialized in psa_generate_random 2018-09-16 12:15:46 +03:00
Gilles Peskine
c6290c043e Minor documentation improvements 2018-09-14 10:02:29 +01:00
Gilles Peskine
4f6c77b0a9 fixup format spec 2018-09-14 10:02:29 +01:00
Gilles Peskine
1be949b846 New macro PSA_KEY_EXPORT_MAX_SIZE
Sufficient buffer size for psa_export_key() and psa_export_public_key().
2018-09-14 10:02:29 +01:00
Gilles Peskine
4e1e9beb56 Define the encoding of ECC and DSA keys 2018-09-14 10:02:29 +01:00
Gilles Peskine
e877974794 Move key type feature test macros to a more logical place 2018-09-14 10:02:29 +01:00
Gilles Peskine
78b3bb670d Change the bitwise encoding of key type categories
There were only 5 categories (now 4). Reduce the category mask from 7
bits to 3.

Combine unformatted, not-necessarily-uniform keys (HMAC, derivation)
with raw data.

Reintroduce a KEY_TYPE_IS_UNSTRUCTURED macro (which used to exist
under the name KEY_TYPE_IS_RAW_DATA macro) for key types that don't
have any structure, including both should-be-uniform keys (such as
block cipher and stream cipher keys) and not-necessarily-uniform
keys (such as HMAC keys and secrets for key derivation).
2018-09-14 10:02:29 +01:00
Jaeden Amero
5ac5cec9a2 Merge pull request #127 from ARMmbed/documentation-update
Update documentation due to function renaming
2018-09-14 10:02:29 +01:00
itayzafrir
ed7382f6a7 Update documentation due to function renaming 2018-09-14 10:02:29 +01:00
mohammad1603
13f43948f3 typo fix 2018-09-14 10:02:29 +01:00
itayzafrir
f26dbfc096 Rearrange PSA_ERROR_XXX error codes
Set PSA_ERROR_UNKNOWN_ERROR as the first error code to prevent the
need to change its value whenever a new error code is added.
2018-09-14 10:02:29 +01:00
Darryl Green
9e2d7a09f1 Add ifdefs for psa_internal_export_key function
MBEDTLS_PK_WRITE_C only requires either MBEDTLS_RSA_C or MBEDTLS_ECP_C to be defined.
Added wrappers to handle the cases where only one has been defined.
Moved mbedtls_pk_init to be within the ifdefs, so it's only called if appropriate.
2018-09-14 10:02:28 +01:00
Darryl Green
8800136156 Fix key parameter in psa_key_derivation to use correct type 2018-09-14 10:02:28 +01:00
Jaeden Amero
cab5494b12 psa: Add license header to crypto.h 2018-09-14 10:02:28 +01:00
Gilles Peskine
edd768775f Fix doxygen warnings
* Broken link #PSA_ALG_SHA_256
* Duplicate group name "generators"
* Missing documentation in psa_generate_key_extra_rsa due to bad magic
  comment marker
2018-09-12 16:50:07 +03:00
Gilles Peskine
9f900a8b25 Merge pull request #105 from ARMmbed/psa-derive_hkdf
PSA key derivation: simple-ish interface, HKDF
2018-09-12 16:50:07 +03:00
Gilles Peskine
9fb0e01177 Fix nonstandard whitespace 2018-09-12 16:50:07 +03:00
Gilles Peskine
bef7f14f8e Implement HKDF 2018-09-12 16:44:05 +03:00
Gilles Peskine
ea0fb4975c Add framework for simple key derivation
New key type PSA_KEY_TYPE_DERIVE. New usage flag PSA_KEY_USAGE_DERIVE.
New function psa_key_derivation.

No key derivation algorithm is implemented yet. The code may not
compile with -Wunused.

Write some unit test code for psa_key_derivation. Most of it cannot be
used yet due to the lack of a key derivation algorithm.
2018-09-12 16:44:04 +03:00