Cryptographic method and apparatus
View Patent ↗A method of formatting data for transmission to another party including the step of incorporating in the data a flag indicative of the absence of data for authentication of the sender. An authentication tag length is also included to permit variable length tags to be used.
1. A method, comprising:
obtaining a message data m and a nonce data N, wherein a value M encoded in the nonce data N indicates a length of an authentication tag, the length of the authentication tag indicates a security level, and the security level inhibits or invokes data confidentiality, and the security level inhibits or invokes data authenticity; and
generating, by a block-cipher, an output c based on the message data m and the nonce data N, wherein the output comprises the authentication tag if the security level invokes data authenticity, and the output comprises the message data m encrypted using the nonce data N and an encryption key K if the security level invokes data confidentiality.
2. The method of claim 1 , wherein the output comprises message data m and the authentication tag if the security level inhibits data confidentiality and invokes data authenticity, wherein the message data m in the output is unencrypted.
3. The method of claim 1 , wherein the authentication tag in the output is unencrypted.
4. The method of claim 1 , wherein the output lacks any authentication tag if the security level inhibits data authenticity.
5. The method of claim 1 , wherein the output comprises plain text if the security level inhibits data confidentiality.
6. The method of claim 1 , wherein the authentication tag comprises a variable-length authentication tag.
7. The method of claim 6 , wherein the values of M comprise 0, 4, 8, 16.
8. The method of claim 1 , wherein if the value M is zero, then data authenticity is disabled.
9. A non-transitory machine-readable medium comprising machine-executable instructions operable when executed to perform operations comprising:
obtaining a message data m and a nonce data N, wherein a value M encoded in the nonce data N indicates a length of an authentication tag, the length of the authentication tag indicates a security level, and the security level inhibits or invokes data confidentiality, and the security level inhibits or invokes data authenticity; and
generating, by a block-cipher, an output c based on the message data m and the nonce data N, wherein the output comprises the authentication tag if the security level invokes data authenticity, and the output comprises the message data m encrypted using the nonce data N and an encryption key K if the security level invokes data confidentiality.
10. The medium of claim 9 , wherein the output comprises message data m and the authentication tag if the security level inhibits data confidentiality and invokes data authenticity, wherein the message data m in the output is unencrypted.
11. The medium of claim 9 , wherein the authentication tag in the output is unencrypted.
12. The medium of claim 9 , wherein the output lacks any authentication tag if the security level inhibits data authenticity.
13. The medium of claim 9 , wherein the output comprises plain text if the security level inhibits data confidentiality.
14. The medium of claim 9 , wherein the authentication tag comprises a variable-length authentication tag.
15. The medium of claim 14 , wherein the values of M comprise 0, 4, 8, 16.
16. The medium of claim 9 , wherein if the value M is zero, then data authenticity is disabled.
17. A device, comprising:
a processor;
memory, the memory comprising computer-executable instructions that, when executed by the processor, perform operations comprising:
obtaining a message data m and a nonce data N, wherein a value M encoded in the nonce data N indicates a length of an authentication tag, the length of the authentication tag indicates a security level, and the security level inhibits or invokes data confidentiality, and the security level inhibits or invokes data authenticity; and
generating, by a block-cipher, an output c based on the message data m and the nonce data N, wherein the output comprises the authentication tag if the security level invokes data authenticity, and the output comprises the message data m encrypted using the nonce data N and an encryption key K if the security level invokes data confidentiality.