Systems and methods for identity-based encryption and related cryptographic techniques
First Claim
1. A method for using identity-based encryption (IBE) to securely convey data over a communications network from a sender to a receiver, comprising:
- at the sender, forming an IBE public key using a time element;
at the sender, obtaining IBE system parameters;
at the sender, encrypting the data using the IBE public key and the IBE system parameters;
at the receiver, receiving the encrypted data from the sender;
at the receiver, obtaining an IBE private key that corresponds to the IBE public key; and
at the receiver, decrypting the encrypted data using the IBE private key, wherein encrypting the data using the IBE public key and the IBE system parameters comprises encrypting the data using the IBE public key, the IBE system parameters, and a bilinear map.
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Accused Products
Abstract
A method and system for encrypting a first piece of information M to be sent by a sender [100] to a receiver [110] allows both sender and receiver to compute a secret message key using identity-based information and a bilinear map. In a one embodiment, the sender [100] computes an identity-based encryption key from an identifier ID associated with the receiver [110]. The identifier ID may include various types of information such as the receiver'"'"'s e-mail address, a receiver credential, a message identifier, or a date. The sender uses a bilinear map and the encryption key to compute a secret message key gIDr, which is then used to encrypt a message M, producing ciphertext V to be sent from the sender [100] to the receiver [110] together with an element rP. An identity-based decryption key dID is computed by a private key generator [120] based on the ID associated with the receiver and a secret master key s. After obtaining the private decryption key from the key generator [120], the receiver [110] uses it together with the element rP and the bilinear map to compute the secret message key gIDr, which is then used to decrypt V and recover the original message M. According to one embodiment, the bilinear map is based on a Weil pairing or a Tate pairing defined on a subgroup of an elliptic curve. Also described are several applications of the techniques, including key revocation, credential management, and return receipt notification.
36 Citations
16 Claims
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1. A method for using identity-based encryption (IBE) to securely convey data over a communications network from a sender to a receiver, comprising:
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at the sender, forming an IBE public key using a time element; at the sender, obtaining IBE system parameters; at the sender, encrypting the data using the IBE public key and the IBE system parameters; at the receiver, receiving the encrypted data from the sender; at the receiver, obtaining an IBE private key that corresponds to the IBE public key; and at the receiver, decrypting the encrypted data using the IBE private key, wherein encrypting the data using the IBE public key and the IBE system parameters comprises encrypting the data using the IBE public key, the IBE system parameters, and a bilinear map. - View Dependent Claims (2, 3, 4, 5)
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6. A method for using identity-based encryption (IBE) to securely convey data over a communications network from a sender to a receiver, wherein the receiver has a credential, comprising:
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at the sender, forming an IBE public key using the credential; at the sender, obtaining IBE system parameters; at the sender, encrypting the data using the IBE public key and the IBE system parameters; at the receiver, receiving the encrypted data from the sender; at the receiver, obtaining an IBE private key that corresponds to the IBE public key; and at the receiver, decrypting the encrypted data using the IBE private key, wherein encrypting the data using the IBE public key and the IBE system parameters comprises encrypting the data using the IBE public key, the IBE system parameters, and a bilinear map. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. An identity-based cryptographic method comprising:
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at a first party, forming an identity-based public key using a time element; at the first party, performing cryptographic operations using the identity-based public key; at a second party, obtaining an identity-based private key corresponding to the identity-based public key; and at the second party, performing cryptographic operations using the identity-based private key, wherein performing the cryptographic operations using the identity-based public key comprises performing the cryptographic operations using the identity-based public key and a bilinear map.
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15. An identity-based cryptographic method comprising:
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at a first party, forming an identity-based public key using a credential of a second party; at the first party, performing cryptographic operations using the identity-based public key; at a second party, obtaining an identity-based private key corresponding to the identity-based public key; and at the second party, performing cryptographic operations using the identity-based private key, wherein performing the cryptographic operations using the identity-based public key comprises performing the cryptographic operations using the identity-based public key and a bilinear map. - View Dependent Claims (16)
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Specification