# US 11,451,521 B2 · Systems and methods for encrypted data transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,521 B2 - Document ID: US11451521B2 - Status: Granted - Kind: B2 - Application number: 16/164,422 - Filed: 2018-10-18 - Published: 2020-04-23 - Granted: 2022-09-20 - Earliest claimed: 2018-10-18 - Assignees: Paypal, Inc. - Applicants: Paypal, Inc. - Inventors: Srini Rangaraj - Web page: https://patentgrep.com/patent/US11451521B2 ## CPC - H04L 63/0442: {wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption (cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30)} - H04L 9/0825: {using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates} - H04L 9/30: Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy - H04L 63/0435: {wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption (cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06)} - H04L 63/0457: {wherein the sending and receiving network entities apply dynamic encryption, e.g. stream encryption (cryptographic mechanisms or cryptographic arrangements for stream encryption H04L9/065)} - H04L 63/061: {for key exchange, e.g. in peer-to-peer networks (cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838)} - H04L 63/166: {at the transport layer} - H04L 63/18: {using different networks or channels, e.g. using out of band channels (cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/0827; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L9/3215)} - H04L 63/20: {for managing network security; network security policies in general (filtering policies H04L63/0227)} - H04L 2463/062: applying encryption of the keys - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Systems and methods for message encryption include transmitting, to a first device through a first communication channel, a modification rule message including a modification rule. A first message is encrypted using a first key to generate an encrypted message. The encrypted message is modified based on the modification rule to generate a modified encrypted message. The modified encrypted message is transmitted to the first device through a second communication channel. ## Claims ### Claim 1 A system, comprising: a non-transitory memory; and one or more hardware processors coupled to the non-transitory memory and configured to read instructions from the non-transitory memory to cause the system to perform operations comprising: transmitting, to a first device through a first communication channel, an encrypted modification rule message including an encrypted modification rule generated by encrypting a modification rule, wherein: the modification rule is configured for use in at least one of modifying a first encrypted message to generate a modified encrypted message or reversing the modified encrypted message; and the modification rule includes one or more of a bit manipulation rule for the modifying the first encrypted message using a bit operation that performs a NOT operation to a plurality of bits of the first encrypted message at a plurality of predetermined locations or a false bit injection rule defining a false bit injection parameter for injecting a false bit into the first encrypted message for the modifying the first encrypted message; encrypting a first message using a first key to generate the first encrypted message; determining a transmission security level associated with transmitting the first encrypted message to the first device; selecting a rule of the modification rule for modifying the first encrypted message based on the transmission security level; modifying the first encrypted message according to the selected rule to generate the modified encrypted message; and transmitting, to the first device through a second communication channel, the modified encrypted message. ### Claim 2 (depends on 1) The system of claim 1, wherein: the first key is a public key associated with the first device; and a private key associated with the first device enables decryption of the modified encrypted message by the first device. ### Claim 3 (depends on 1) The system of claim 1, wherein the first key includes a secret key used for decryption at the first device, and wherein the operations further comprise: encrypting the secret key using a public key of the first device to generate an encrypted secret key message; and transmitting, to the first device through a third communication channel, the encrypted secret key message, wherein a private key associated with the first device enables decryption of the transmitted encrypted secret key message by the first device, and wherein the secret key enables decryption of the transmitted modified encrypted message by the first device. ### Claim 4 (depends on 1) The system of claim 1, wherein the first communication channel comprises Email, Webpage, phone, fax, or Secure File Transfer Protocol (SFTP). ### Claim 5 (depends on 1) The system of claim 1, wherein the first communication channel is different from the second communication channel. ### Claim 6 A method, comprising: transmitting, to a first device through a first communication channel, an encrypted modification rule message including an encrypted modification rule generated by encrypting a modification rule, wherein: the modification rule is configured for use in at least one of modifying a first encrypted message or reversing the modified encrypted message; and the modification rule includes one or more of a bit manipulation rule for the modifying the first encrypted message using a bit operation that performs a NOT operation to a plurality of predetermined bits of the first encrypted message or a false bit injection rule defining a false bit injection parameter for injecting a false bit into the first encrypted message for the modifying the first encrypted message; encrypting a first message to generate the first encrypted message; determining a transmission security level associated with transmitting the first encrypted message to the first device; selecting a rule of the modification rule for modifying the first encrypted message based on the transmission security level; modifying the first encrypted message according to the selected rule to generate the modified encrypted message; and transmitting, to the first device through a second communication channel, the modified encrypted message. ### Claim 7 (depends on 6) The method of claim 6, wherein: the first message is encrypted using a public key associated with the first device. ### Claim 8 (depends on 6) The method of claim 6, wherein the first message is encrypted using a secret key, wherein the method further comprises: encrypting the secret key using a public key of the first device to generate an encrypted secret key message; and transmitting, to the first device through a third communication channel, the encrypted secret key message. ### Claim 9 (depends on 6) The method of claim 6, wherein the first communication channel comprises Email, Webpage, phone, fax, or Secure File Transfer Protocol (SFTP). ### Claim 10 (depends on 6) The method of claim 6, wherein the first communication channel is different from the second communication channel. ### Claim 11 A non-transitory machine-readable medium having stored thereon machine-readable instructions executable to cause a machine to perform operations comprising: transmitting, to a first device through a first communication channel, an encrypted modification rule message including an encrypted modification rule generated by encrypting a modification rule, wherein: the modification rule is configured for use in at least one of modifying a first encrypted message to generate a modified encrypted message or reversing the modified encrypted message; and the modification rule includes one or more of a bit manipulation rule for the modifying the first encrypted message using a bit operation that reverses a plurality of bits of the first encrypted message at a plurality of predetermined locations or a false bit injection rule defining a false bit injection parameter for injecting a false bit into the first encrypted message for the modifying the first encrypted message; encrypting a first message using a first key to generate the first encrypted message; determining a transmission security level associated with transmitting the first encrypted message to the first device; selecting a rule of the modification rule for modifying the first encrypted message based on the transmission security level; modifying the first encrypted message according to the selected rule to generate the modified encrypted message; and transmitting, to the first device through a second communication channel, the modified encrypted message. ### Claim 12 (depends on 11) The non-transitory machine-readable medium of claim 11, wherein: the first key is a public key associated with the first device. ### Claim 13 (depends on 11) The non-transitory machine-readable medium of claim 11, wherein the first key includes a secret key for decryption at the first device, wherein the operations further comprise: encrypting the secret key using a public key of the first device to generate an encrypted secret key message; and transmitting, to the first device through a third communication channel, the encrypted secret key message. ### Claim 14 (depends on 11) The non-transitory machine-readable medium of claim 11, wherein the first communication channel comprises Email, Webpage, phone, fax, or Secure File Transfer Protocol (SFTP). ### Claim 15 (depends on 1) The system of claim 1, wherein the encrypted modification rule is configured to be decrypted at the first device to recover the modification rule such that the modification rule is able to be used by the first device to reverse the modified encrypted message. ### Claim 16 (depends on 1) The system of claim 1, wherein the false bit injection parameter includes one or both of a pattern of the false bit and a location in the first encrypted message for the injecting the false bit into the first encrypted message. ### Claim 17 (depends on 1) The system of claim 1, wherein the transmission security level is determined based on a property of a device of the system configured to transmit the first encrypted message. ### Claim 18 (depends on 6) The method of claim 6, wherein the transmission security level is determined based on a type of a transaction that includes the transmitting the first encrypted message or a time the transaction is occurring. ### Claim 19 (depends on 6) The method of claim 6, wherein the modification rule is configured to be changed based on a type of a transaction that includes the transmitting the first encrypted message, the type of the transaction including a payment transaction. ### Claim 20 (depends on 11) The non-transitory machine-readable medium of claim 11, wherein the first communication channel is different from the second communication channel.