fromBase64toSha256 method
Converts given Base64 String to SHA-256 format String.
Throws FormatException if given value
cannot be a valid SHA-256 hash.
Returns base64 encoded String.
Implementation
String fromBase64toSha256(String value) {
final List<int> bytes = base64.decode(value);
final hexForm = hex.encode(bytes);
if (!isValidSha256Format(hexForm)) {
throw const FormatException('Value is not SHA-256');
}
final sha256Form = _formatSha(hexForm);
return sha256Form;
}