Updated: 2022/Sep/29

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EVP_MD-SHAKE(7)                     OpenSSL                    EVP_MD-SHAKE(7)



NAME
       EVP_MD-SHAKE, EVP_MD-KECCAK-KMAC - The SHAKE / KECCAK family EVP_MD
       implementations

DESCRIPTION
       Support for computing SHAKE or KECCAK-KMAC digests through the EVP_MD
       API.

       KECCAK-KMAC is a special digest that's used by the KMAC EVP_MAC
       implementation (see EVP_MAC-KMAC(7)).

   Identities
       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)

       KECCAK-KMAC-256
           Known names are "KECCAK-KMAC-256" and "KECCAK-KMAC256" This is used
           by EVP_MAC-KMAC256(7)

       SHAKE-128
           Known names are "SHAKE-128" and "SHAKE128"

       SHAKE-256
           Known names are "SHAKE-256" and "SHAKE256"

   Gettable Parameters
       This implementation supports the common gettable parameters described
       in EVP_MD-common(7).

   Settable Context Parameters
       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.

SEE ALSO
       EVP_MD_CTX_set_params(3), provider-digest(7), OSSL_PROVIDER-default(7)

COPYRIGHT
       Copyright 2020-2022 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
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-05-07                   EVP_MD-SHAKE(7)