ASP.NET Core JWT支持多种哈希算法来生成JWT令牌，包括HmacSha256、HmacSha384和HmacSha512等。在使用HmacSha512算法和HmacSha512Signature算法生成JWT令牌时，它们的主要区别在于密钥和签名的计算方式不同。

下面是使用HmacSha512算法的代码示例：

var keyBytes = Encoding.UTF8.GetBytes("your_secret_key");
var signingKey = new SymmetricSecurityKey(keyBytes);

var signingCredentials = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha512);

var token = new JwtSecurityToken(
    issuer: "your_issuer",
    audience: "your_audience",
    claims: new List(),
    notBefore: DateTime.UtcNow,
    expires: DateTime.UtcNow.AddDays(7),
    signingCredentials: signingCredentials);

var jwtToken = new JwtSecurityTokenHandler().WriteToken(token);

下面是使用HmacSha512Signature算法的代码示例：

var keyBytes = Encoding.UTF8.GetBytes("your_secret_key");
var signingKey = new SymmetricSecurityKey(keyBytes);

var signatureProvider = new HmacSha512SignatureProvider(signingKey);
var signatureCredentials = new SigningCredentials(signatureProvider, SecurityAlgorithms.HmacSha512Signature);

var token = new JwtSecurityToken(
    issuer: "your_issuer",
    audience: "your_audience",
    claims: new List(),
    notBefore: DateTime.UtcNow,
    expires: DateTime.UtcNow.AddDays(7),
    signingCredentials: signatureCredentials);

var jwtToken = new JwtSecurityTokenHandler().WriteToken(token);

通过对比上述两段代码，可以看出区别主要在于签名凭证的生成方式不同，但都是使用的HmacSha512哈希算法来生成签名。