PBC Library Manual 0.5.11 - Stanford Crypto Group

element_t sig;
element_t temp1, temp2;
element_init_G2(g, pairing);
element_init_G2(public_key, pairing);
element_init_G1(h, pairing);
element_init_G1(sig, pairing);
element_init_GT(temp1, pairing);
element_init_GT(temp2, pairing);
element_init_Zr(secret_key, pairing);
generate system parameters,
element_random(g);
generate a private key,
element_random(secret_key);
and the corresponding public key.
element_pow_zn(public_key, g, secret_key);
Chapter 2. Tutorial
When given a message to sign, we first compute its hash, using some standard hash algorithm. Many
libraries can do this, and this operation does not involve pairings, so PBC does not provide functions for
this step. For this example, and our message has already been hashed, possibly using another library.
Say the message hash is "ABCDEF" (a 48-bit hash). We map these bytes to an element h of G1,
element_from_hash(h, "ABCDEF", 6);
then sign it:
element_pow_zn(sig, h, secret_key);
To verify this signature, we compare the outputs of the pairing applied to the signature and system
parameter, and the pairing applied to the message hash and public key. If the pairing outputs match then
the signature is valid.
pairing_apply(temp1, sig, g, pairing);
pairing_apply(temp2, h, public_key, pairing);
if (!element_cmp(temp1, temp2)) {
printf("signature verifies\n");
} else {
printf("signature does not verify\n");
}
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