For our privacy-preserving protocol, an encrypted channel is established. In order to protect our system from man-in-the-middle attacks, signature-based approach is used. After we've implemented it with RSA, we decided to optimize the protocol a bit by using ECDSA. The result was very surprising: on Android, signing and verifying in case of ECDSA was 10 times slower than for RSA with the corresponding key length!
Any viable explanation for this?
Maybe the android smart phones don't have hardware support for elliptic curves, and for RSA operations they do?
The exact parameters are below:
RSA: signing: 52ms, verifying: 6ms ECDSA: signing: 692ms, verifying: 975ms Smartphone: Samsung Galaxy S Advance, GT-I9070P with CPU: 1 GHz STE U8500 DualCore Crypto-lib: SpongyCastle 22.214.171.124 Elliptic curve used: 224 bit, secp224r1 ECC signature: SHA256 with ECDSA RSA 2048 signature: SHA1 with RSA