Sortix nightly manual
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|EVP_DIGESTVERIFYINIT(3)||Library Functions Manual||EVP_DIGESTVERIFYINIT(3)|
EVP signature verification functions
EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx, const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey); int
EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt); int
EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig, size_t siglen); int
EVP_DigestVerify(EVP_MD_CTX *ctx, const unsigned char *sig, size_t siglen, const unsigned char *tbs, size_t *tbslen);
EVP_DigestVerifyInit() sets up verification context ctx to use digest type from ENGINE e and public key pkey. ctx must be initialized with EVP_MD_CTX_init(3) before calling this function. If pctx is not
NULL, the EVP_PKEY_CTX of the verification operation will be written to *pctx: this can be used to set alternative verification options. Any existing value in *.Fa pctx is overwritten. The EVP_PKEY_CTX value returned must not be freed directly by the application. It will be freed automatically when the EVP_MD_CTX is freed.
EVP_DigestVerifyUpdate() hashes cnt bytes of data at d into the verification context ctx. This function can be called several times on the same ctx to include additional data. This function is currently implemented using a macro.
EVP_DigestVerifyFinal() verifies the data in ctx against the signature in sig of length siglen.
EVP_DigestVerify() verifies tbslen bytes at tbs against the signature in sig of length siglen.
EVP_DigestVerify() is a one shot operation which verifies a single block of data in one function call. For algorithms that support streaming it is equivalent to calling
EVP_DigestVerifyFinal(). The EVP interface to digital signatures should almost always be used in preference to the low level interfaces. This is because the code then becomes transparent to the algorithm used and much more flexible. The call to
EVP_DigestVerifyFinal() internally finalizes a copy of the digest context. This means that EVP_VerifyUpdate(3) and EVP_VerifyFinal(3) can be called later to digest and verify additional data. Since only a copy of the digest context is ever finalized, the context must be cleaned up after use by calling EVP_MD_CTX_free(3) or a memory leak will occur.
EVP_DigestVerifyUpdate() return 1 for success and 0 for failure.
EVP_DigestVerify() return 1 for success; any other value indicates failure. A return value of 0 indicates that the signature did not verify successfully (that is, the signature did not match the original data or the signature had an invalid form), while other values indicate a more serious error (and sometimes also indicate an invalid signature form). The error codes can be obtained from ERR_get_error(3). evp(3), EVP_DigestInit(3), EVP_DigestSignInit(3), EVP_PKEY_meth_set_verifyctx(3)
EVP_DigestVerifyFinal() first appeared in OpenSSL 1.0.0 and have been available since OpenBSD 4.9.
EVP_DigestVerify() first appeared in OpenSSL 1.1.1 and has been available since OpenBSD 7.0.
|January 15, 2022||Debian|