Crypto API

The crypto API is available from the full node via websockets.
Blinding and Un-Blinding
blind
Get signed blocks.
Generates a Pedersen Commitment: *commit = blind * G + value * G2. The commitment is 33 bytes, the blinding factor is 32 bytes.
Tip: For more information about Pedersen Commitment see: Commitment Scheme​
commitment_type graphene::app::crypto_api::blind(
    const fc::ecc::blind_factor_type &blind, 
    uint64_t value)
Parameters
Return
blind: Sha-256 blind factor type
value: Positive 64-bit integer value
A 33-byte Pedersen Commitment: commit = blind G + value * G2
blind_sum
Get SHA-256 blind factor type.
blind_factor_type graphene::app::crypto_api::blind_sum(
    const std::vector<blind_factor_type> &blinds_in, 
    uint32_t non_neg)
Parameters
Return
blinds_in: List of SHA-256 blind factor types
non_neg: 32-bit integer value
A blind factor type.
Range Proofs
range_get_info
Gets “range proof” information.
The cli_wallet includes functionality for sending blind transfers in which the values of the input and output amounts are “blinded.”
Note: In the case where a transaction produces two or more outputs, (e.g. an amount to the intended recipient plus “charge” back to the sender), a “range proof” must be supplied to prove that none of the outputs commit to a negative value.
range_proof_info graphene::app::crypto_api::range_get_info(
    const std::vector<char> &proof)
Parameters
Return
proof: List of proof’s characters
A range proof info structure with exponent, mantissa, min and max values.
range_proof_sign
Proves with respect to min_value the range for Pedersen Commitment which has the provided blinding factor and value.
std::vector<char> graphene::app::crypto_api::range_proof_sign(
    uint64_t min_value, 
    const commitment_type &commit, 
    const blind_factor_type &commit_blind, 
    const blind_factor_type &nonce, 
    int8_t base10_exp, 
    uint8_t min_bits, 
    uint64_t actual_value
Parameters
Return
min_value: Positive 64-bit integer value
commit: 33-byte pedersen commitment
commit_blind: Sha-256 blind factor type for the correct digits
nonce: Sha-256 blind factor type for our non-forged signatures
base10_exp: Exponents base 10 in range [-1 ; 18] inclusively
min_bits: 8-bit positive integer, must be in range [0 ; 64] inclusively
actual_value: 64-bit positive integer, must be greater or equal min_value
A list of characters as proof in proof.
Verification
verify_sum
Verifies that commits + neg_commits + excess == 0.
bool graphene::app::crypto_api::verify_sum(
    const std::vector<commitment_type> &commits_in, 
    const std::vector<commitment_type> &neg_commits_in, 
    int64_t excess)
Parameters
Return
commits_in: List of 33-byte Pedersen Commitments
neg_commits_in: List of 33-byte Pedersen Commitments
excess: Sum of two list of 33-byte Pedersen Commitments where sums the first set and subtracts the second
(Boolean) True in event of commits + neg_commits + excess == 0, otherwise false
verify_range
Verifies range proof for 33-byte Pedersen Commitment.
verify_range_result graphene::app::crypto_api::verify_range(
    const fc::ecc::commitment_type &commit, 
    const std::vector<char> &proof)
Parameters
Return
commit: 33-byte pedersen commitment
proof: List of characters
A structure with success, min and max values
verify_range_proof_rewind
Verifies range proof rewind for 33-byte Pedersen Commitment.
verify_range_proof_rewind_result graphene::app::crypto_api::verify_range_proof_rewind(
    const blind_factor_type &nonce, 
    const fc::ecc::commitment_type &commit, 
    const std::vector<char> &proof)
Parameters
Return
nonce: Sha-256 blind refactor type
commit: 33-byte pedersen commitment
proof: List of characters
A structure with success, min, max, value_out, blind_out and message_out values.
Block API
Database API