State-maintained multi-party signatures
View Patent ↗A hash module of a mail sender creates a hash data context structure. The hash module processes the headers and the body of an e-mail message in the order required, for example by the DKIM specification, until the data to be hashed has been input. The hash module converts the context structure into printable characters and the encoded structure is transmitted over the Internet or other network to the next participating system. The token authority's hash module decodes the context back into binary form. After ensuring business logic is satisfied, it generates additional headers required for signature, which are then added to the developing hash. The hash module finalizes the hash function and creates the hash value. The authorization module creates the signature and returns it to the e-mail module, which attaches the signature to the message and transmits it to the destination mailbox provider, which verifies the token.
1. A method for certifying an email message not known in its entirety by any one of multiple parties, the e-mail including a plurality of headers and a message body, the method comprising:
creating at a first computer operated by a mail sender, a data context for holding a state of an in-process hash, said data context comprising at least a 64-byte long internal buffer, five integers that hold the internal state, an internal counter, and a byte order endian flag; processing data including a plurality of the headers and the message body portion of the message known by the email sender according to a hash function;
storing in the data context in consecutive memory a state of the processed data portion of the message known by the email sender; creating a representation of the state of the processed data portion of the message known by the email sender, the representation including printable characters; and transmitting the representation of the state of the processed data portion over a network to a second computer operated by a mail signer.
2. The method of a claim 1 further comprising:
receiving, at the second computer operated by a mail signer, the transmitted representation of the state of the processed data portion;
decoding the received representation to obtain in consecutive memory the state of the processed data portion of the message known by the email sender;
generating a second plurality of headers; creating a hash value based on the hash function, the state of the processed data portion of the message known by the email sender, and the second plurality of headers; and
associating a digital signature with the hash value.
3. A computer program product for certifying an email message not known in its entirety by any one of multiple parties, the e-mail including a plurality of headers and a message body, the computer program product stored on a non-transitory computer-readable medium and including code that, when executed by a first processor, causes a first computer to carry out steps comprising: creating at a first computer operated by a mail sender, a data context for holding a state of an in-process hash, said data context comprising at least a 64-byte long internal buffer, five integers that hold the internal state, an internal counter, and a byte order endian flag;
processing data including a plurality of the headers and the message body portion of the message known by the email sender according to a hash function;
storing in the data context in consecutive memory a state of the processed data portion of the message known by the email sender; creating a representation of the state of the processed data portion of the message known by the email sender, the representation including printable characters; and transmitting the representation of the state of the processed data portion over a network to a second computer operated by a mail signer.
4. The computer program product of a claim 3 further including code that, when executed by a second processor, causes a second computer to carry out steps comprising:
receiving, at the second computer operated by a mail signer, the transmitted representation;
decoding the received representation to obtain in consecutive memory the state of the processed data portion of the message known by the email sender;
generating a second plurality of headers;
creating a hash value based on the hash function, the state of the processed data portion of the message known by the email sender, and the second plurality of headers; and
associating a digital signature with the hash value.