EVP_MD-SHAKE, EVP_MD-KECCAK-KMAC - The SHAKE / KECCAK family EVP_MD
implementations
Support for computing SHAKE or KECCAK-KMAC digests through the
EVP_MD
API.
KECCAK-KMAC is an Extendable Output Function (XOF), with a definition similar to
SHAKE, used by the KMAC EVP_MAC implementation (see
EVP_MAC-KMAC(7)).
This implementation is available in the FIPS provider as well as the default
provider, and includes the following varieties:
- KECCAK-KMAC-128
- Known names are "KECCAK-KMAC-128" and
"KECCAK-KMAC128". This is used by EVP_MAC-KMAC128(7).
Using the notation from NIST FIPS 202 (Section 6.2), we have
KECCAK-KMAC-128(M, d) =
KECCAK[256](M || 00, d) (see the description of
KMAC128 in Appendix A of NIST SP 800-185).
- KECCAK-KMAC-256
- Known names are "KECCAK-KMAC-256" and
"KECCAK-KMAC256". This is used by EVP_MAC-KMAC256(7).
Using the notation from NIST FIPS 202 (Section 6.2), we have
KECCAK-KMAC-256(M, d) =
KECCAK[512](M || 00, d) (see the description of
KMAC256 in Appendix A of NIST SP 800-185).
- SHAKE-128
- Known names are "SHAKE-128" and
"SHAKE128".
- SHAKE-256
- Known names are "SHAKE-256" and
"SHAKE256".
This implementation supports the common gettable parameters described in
EVP_MD-common(7).
These implementations support the following
OSSL_PARAM(3) entries,
settable for an
EVP_MD_CTX with
EVP_MD_CTX_set_params(3):
- "xoflen" (OSSL_DIGEST_PARAM_XOFLEN)
<unsigned integer>
- Sets the digest length for extendable output functions. The
length of the "xoflen" parameter should not exceed that of a
size_t.
For backwards compatibility reasons the default xoflen length for SHAKE-128
is 16 (bytes) which results in a security strength of only 64 bits. To
ensure the maximum security strength of 128 bits, the xoflen should be set
to at least 32.
For backwards compatibility reasons the default xoflen length for SHAKE-256
is 32 (bytes) which results in a security strength of only 128 bits. To
ensure the maximum security strength of 256 bits, the xoflen should be set
to at least 64.
EVP_MD_CTX_set_params(3),
provider-digest(7),
OSSL_PROVIDER-default(7)
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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
<
https://www.openssl.org/source/license.html>.