Abstract: A system and methods are provided for establishing an authenticated and encrypted communication connection between two devices with at most two round-trip communications. During establishment of an initial authenticated, encrypted communication connection (or afterward), a first device (e.g., a server) provides the second device (e.g., a client) with a token (e.g., a challenge) that lives or persists beyond the current connection. After that connection is terminated and the second device initiates a new connection, it uses the token as part of the handshaking process to reduce the necessary round-trip communications to one.

Abstract: A system and method for detecting unwanted electronic content, such as spam. As a user operates an application to send messages, several metrics are tracked to allow the system to analyze her activity. Illustrative metrics may include, but are not limited to, block count (e.g., how many other users have blocked her), block rate (e.g., the rate at which other users block her), peer symmetry (e.g., percentage of her messages that are to other users that have her in their address book), message uniqueness (e.g., how unique her messages are from each other), peer uniqueness (e.g., how unique the addressees of her messages are), and message rate (e.g., the rate at which she sends messages). Periodically, metrics may be compared to corresponding thresholds. Depending on whether a threshold is crossed, and which threshold is crossed, she may be banned from using the application or placed on a watch list.

Abstract: A system and method for detecting unwanted electronic content, such as spam. As a user operates an application to send messages, several metrics are tracked to allow the system to analyze her activity. Illustrative metrics may include, but are not limited to, block count (e.g., how many other users have blocked her), block rate (e.g., the rate at which other users block her), peer symmetry (e.g., percentage of her messages that are to other users that have her in their address book), message uniqueness (e.g., how unique her messages are from each other), peer uniqueness (e.g., how unique the addressees of her messages are), and message rate (e.g., the rate at which she sends messages). Periodically, metrics may be compared to corresponding thresholds. Depending on whether a threshold is crossed, and which threshold is crossed, she may be banned from using the application or placed on a watch list.

Abstract: A system and methods are provided for establishing an authenticated and encrypted communication connection between two devices with at most two round-trip communications. During establishment of an initial authenticated, encrypted communication connection (or afterward), a first device (e.g., a server) provides the second device (e.g., a client) with a token (e.g., a challenge) that lives or persists beyond the current connection. After that connection is terminated and the second device initiates a new connection, it uses the token as part of the handshaking process to reduce the necessary round-trip communications to one.

Abstract: A system and method for detecting unwanted electronic content, such as spam. As a user operates an application to send messages, several metrics are tracked to allow the system to analyze her activity. Illustrative metrics may include, but are not limited to, block count (e.g., how many other users have blocked her), block rate (e.g., the rate at which other users block her), peer symmetry (e.g., percentage of her messages that are to other users that have her in their address book), message uniqueness (e.g., how unique her messages are from each other), peer uniqueness (e.g., how unique the addressees of her messages are), message rate (e.g., the rate at which she sends messages). Periodically, metrics may be compared to corresponding thresholds. Depending on whether a threshold is crossed, and which threshold is crossed, she may be banned from using the application or placed on a watch list.