Fecha de publicación: -- Fuente: Wipo "digitalization" The present invention relates to an encrypting/decrypting method for a multi-digit number and an encrypting/decrypting server. The encrypting method comprises: after receiving a preset type of multi-digit number to be encrypted, according to a pre-determined encrypting digit determination rule, determining a number segment to be encrypted having a first preset number of digits and a non-encrypting number segment except the number segment to be encrypted; performing operational processing on the determined non-encrypting number segment using a pre-defined encrypting cryptographic algorithm and key corresponding to the multi-digit number to be encrypted to generate an operational value; performing an encrypting mixing operation on the number segment to be encrypted and the generated operational value using a pre-determined encrypting mixing operation algorithm to obtain a mixingly encrypted number segment having the first preset number of digits; and replacing the number segment to be encrypted in the preset type of multi-digit number to be encrypted with the mixingly encrypted number segment to generate an encrypted multi-digit number. The method improves the security of the protection to a multi-digit number.