EVP_CIPHER-SM4 - The SM4 EVP_CIPHER implementations
Support for SM4 symmetric encryption using the EVP_CIPHER API.
The following algorithms are available in the default provider:
This implementation supports the parameters described in "PARAMETERS" in EVP_EncryptInit(3).
SM4 implementations in OpenSSL may use secret-dependent table lookups and are not guaranteed to be constant-time. In particular, the portable C implementation uses S-box and T-table lookups and may be vulnerable to cache-timing side-channel attacks. Which code path is used depends on CPU capabilities; see OPENSSL_armcap(3), OPENSSL_ia32cap(3) and OPENSSL_riscvcap(3).
The SM4-XTS implementation allows streaming to be performed, but each EVP_EncryptUpdate(3) or EVP_DecryptUpdate(3) call requires each input to be a multiple of the blocksize. Only the final EVP_EncryptUpdate() or EVP_DecryptUpdate() call can optionally have an input that is not a multiple of the blocksize but is larger than one block. In that case ciphertext stealing (CTS) is used to fill the block.
OPENSSL_armcap(3), OPENSSL_ia32cap(3), OPENSSL_riscvcap(3), OSSL_PROVIDER-default(7), provider-cipher(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.