Public/private key system with increased security

Some embodiments relate to a second cryptographic device (20) and a first cryptographic device (10). The first and second cryptographic devices may be configured to transmit a key seed. The key seed may be protected using a public key from one party and a private key from the other party. For example, a public key may be obtained from a private key by noise multiplication. At least one of the first and second cryptographic devices may verify the obtained public key, e.g., to avoid leakage of a key seed or a private key. 一些实施例涉及第二密码设备(20)和第一密码设备(10)。第一和第二密码设备可以被配置为传送密钥种子。密钥种子可以使用来自一方的公钥和来自另一方的私钥来保护。例如，可以通过噪声相乘从私钥获得公钥。第一和第二密码设备中的至少一个可以验证获得的公钥，例如，以避免密钥种子或私钥的泄露。