Blind signature is commonly used in electronic transactions to protect the anonymity of users on a computer network as required. In practice, besides the type of single blind signature scheme (with a blind signer), there are many applications may require more than one blind signer on an electronic message. In which, an electronic message is first blinded then passed to each of the signers, who then signs it using a signature protocol such as multisignature protocol. And in this case, all the signers are generally using a protocol known as blind multisignature. Typically, most of the developed blind signatures are based on a single difficult problem. If one finds a solution to this problem then the blind schemes are breakable. Therefore, to improve the security of digital signature schemes, they can be built based on a simultaneous combination of multiple hard problems. This paper proposed a new blind signature scheme and a new blind muttisignature protocol. Mathematical basis of the schemes are based on the difficulty of combining both the discrete logarithm problems: on the integer field and on the elliptic curve. There are first blind signature schemes proposed based on the combination of two hard problems: DLP and ECDLP.