Syntax:
asymmetric_verify(algorithm, text, sig_str, pub_key_str, digest_type)

Verifies whether the signature string matches the digest string, and
returns 1 or 0 to indicate whether verification succeeded or failed. If
verification fails, the result is NULL.

For the legacy version of this function in use before MySQL 8.0.29, see
https://dev.mysql.com/doc/refman/8.0/en/enterprise-encryption-functions
-legacy.html.

By default, the component_enterprise_encryption function assumes that
signatures use the RSASSA-PSS signature scheme. The function supports
verification for signatures produced by the legacy openssl_udf shared
library functions if the system variable
enterprise_encryption.rsa_support_legacy_padding is set to ON (the
default is OFF). When ON is set, the function also supports the
RSASSA-PKCS1-v1_5 signature scheme, as used by the legacy openssl_udf
shared library functions. When OFF is set, signatures produced by the
legacy functions cannot be verified, and the function returns null
output for such content.

algorithm is the encryption algorithm used to create the key. The
supported algorithm value is 'RSA'.

text is a data string or digest string. The component function accepts
digests but does not require them, as it is also capable of handling
data strings of an arbitrary length. A digest string can be generated
by calling create_digest().

sig_str is the signature string to be verified. A signature string can
be generated by calling asymmetric_sign().

pub_key_str is the public key string of the signer. It corresponds to
the private key passed to asymmetric_sign() to generate the signature
string. It must be a valid PEM encoded RSA public key.

digest_type is the algorithm that was used to sign the data. The
supported digest_type values are 'SHA224', 'SHA256', 'SHA384', and
'SHA512' when OpenSSL 1.0.1 is in use. If OpenSSL 1.1.1 is in use, the
additional digest_type values 'SHA3-224', 'SHA3-256', 'SHA3-384', and
'SHA3-512' are available.

URL: https://dev.mysql.com/doc/refman/8.0/en/enterprise-encryption-functions.html

