Co-Signer Transaction Signature Verification

Co-Signer provides a more secure dual-verification feature for transactions.

In addition to the Co-Signer callback mechanism, Clients can simultaneously pass the sign field when initiating a transaction. Co-Signer will additionally verify whether the sign is legal.

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Specific signature rules are as follows

• Sign the parameters in the format k1=v1&k2=v2, and sort k in ASCII ascending order; parameters with empty values are not included in the signature.

• The digits involved in the signature must not end with the digit 0, for example, 1.0001000, please use 1.0001 for the signature.

• After concatenating the parameters, convert to lowercase and then use MD5 encryption. For example, if the parameters before encryption are address_to=0x5edc9177997bf6b4db559a5c184051858b3b3704&amount=1.0001, the MD5 encryption result is c10c47a46b616526e739985ce1c7f15d.

• Use the SHA256 algorithm to sign the MD5 data with RSA, and then encode it with BASE64 to obtain the final signature data.