Gets or sets the digest algorithm for the byte range digest and the signed attributes: SHA-256, SHA-384, SHA-512 or, as
HashAlgorithmNames named SHA3-256, SHA3-384 and SHA3-512, the SHA-3 digests.
null (the default) picks the one the signer's key calls for: SHA-384 for an ECDSA key on P-384, SHA-512 on
P-521, SHA-256 otherwise.
public HashAlgorithmName? DigestAlgorithm { get; set; }
ISO 32000-2 §12.8.3.1, Table 260: SHA-256 (PDF 1.6), SHA-384 and SHA-512 (PDF 1.7). ISO/TS 32001 §5.1.4: SHA3-256, SHA3-384 and SHA3-512 (PDF 2.0 with the ISO/TS 32001 developer extension, which signing declares). An ECDSA key takes only the digests of its curve's size (ISO/TS 32002 §5.1.3, Table 3): signing refuses another.