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Chapter 2 Algorithm Info Types 67
AI_EC_DSA
Key info types for keyObject in B_SignInit:
KI_ECPrivate or KI_ECPrivateBER.
Key info types for keyObject in B_VerifyInit:
KI_ECPublic or KI_ECPublicBER.
Input constraints:
In practice, the input to the ECDSA algorithm — that is, the data to sign — is
generally the result of a digest operation. In Crypto-C’s implementation, however, the
only restrictions on the input are that it must be at least 16 bytes and no more than 32
bytes long.
Output considerations:
The
signature
result of B_SignFinal is the concatenation of the signature elements
(r,s), as defined in section 5.3.1 of the X9.57 Draft. The size of
signature
is 2*(length of
order) bytes. For instance, if the order is 160 bits (20 bytes), the
signature
will be 40
bytes long.