Electronic transactions require secure electronic signature techniques, which can provide the authentication of the signing individual, non-repudiation of the signature and protection of the integrity of the document using strong cryptographic methods. The weakest link in the chain in current electronic signature systems is the correspondence between the person and the secret key. The basic idea of our proposed method is to store the secret key encoded in a fingerprint in a way that it can only be retrieved using the fingerprint of its owner. This way it is much harder to steal the private key, since the creation of the signature requires the presence of the owner's fingerprint instead of the use of a PIN code in today's practice. Our scheme remains fully compatible with the existing Public Key Infrastructures (PKI), so it can be easily used in current applications that use asymmetric cryptography to verify digital signatures.