Dan Boneh Craig Gentry Ben Lynn Hovav Shacham Aggregate and Verifiably Encrypted Signatures from Bilinear Maps. 416-432 2003 conf/eurocrypt/2003 EUROCRYPT http://link.springer.de/link/service/series/0558/bibs/2656/26560416.htm db/conf/eurocrypt/eurocrypt2003.html#BonehGLS03