Base64Decode base64 decode.

Base64Encode base64 encode StdEncoding is the standard base64 encoding, as defined in RFC 4648.

Base64Encode1 Base64Encode1.

GoogleAuth time slice is 30 second, if the key is invalid, return code is zero and ignore the error.

MD5 生成字符串的MD5值.

TotpToken implements TOTP Algorithm, based on HOTP.