Hello
I have created a signature of a chunk of text using the following OpenSSL CLI command:
echo -n "sample text" | openssl dgst -sha1 -binary | openssl rsautl -sign -inkey "privatekey.pem"
Basically what it does it calculating sha1 digest of text, and then signing this calculated digest as a binary blob with OpenSSL RSA signing using a private key in a PEM format.
Now I would like to verify whether this "sample text" was signed by the owner of the privatekey.pem using a matching publickey.pem file, from within a macOS application.
I can easily verify the signature by "decrypting" it using openssl dylib, something like this:
(this will return me an original SHA1 digest, which I can then compare with the original string's SHA1 digest)
However I wouldn't like to have any dependencies on openssl, and would like to move to MacOS security libraries
I ended up attempting to use Security framework, since it is supported in earlier versions of macOS (I need all the way back to High Sierra).
What I am doing is the following:
This gives me an error: SecKeyCreateDecryptedData errorError Domain=NSOSStatusErrorDomain Code=-50 "RSAdecrypt wrong input (err -27)" (paramErr: error in user parameter list) UserInfo={numberOfErrorsDeep=0, NSDescription=RSAdecrypt wrong input (err -27)}
Note that OpenSSL code above can decrypt this with RSA_PKCS1_PADDING argument.
If instead of kSecKeyAlgorithmRSAEncryptionPKCS1 I put kSecKeyAlgorithmRSAEncryptionRaw, I do get some bytes and no errors, however they are incorrect, as OpenSSL CLI uses PKCS1.
Is there a way to get a matching to OpenSSL signature verification via macOS APIs?
I have created a signature of a chunk of text using the following OpenSSL CLI command:
echo -n "sample text" | openssl dgst -sha1 -binary | openssl rsautl -sign -inkey "privatekey.pem"
Basically what it does it calculating sha1 digest of text, and then signing this calculated digest as a binary blob with OpenSSL RSA signing using a private key in a PEM format.
Now I would like to verify whether this "sample text" was signed by the owner of the privatekey.pem using a matching publickey.pem file, from within a macOS application.
I can easily verify the signature by "decrypting" it using openssl dylib, something like this:
Code Block int returnedDigestSize = RSA_public_decrypt((int)signatureLength, signatureBytes, destination, rsa_key, RSA_PKCS1_PADDING);
(this will return me an original SHA1 digest, which I can then compare with the original string's SHA1 digest)
However I wouldn't like to have any dependencies on openssl, and would like to move to MacOS security libraries
I ended up attempting to use Security framework, since it is supported in earlier versions of macOS (I need all the way back to High Sierra).
What I am doing is the following:
Code Block NSData *pubKeyData = [kPublicRSAKey dataUsingEncoding:NSUTF8StringEncoding]; SecExternalFormat keyFormat = kSecFormatOpenSSL; SecExternalItemType keyType = kSecItemTypePublicKey; CFArrayRef cfImportedItems = NULL; OSStatus retval = 0; retval = SecItemImport((CFDataRef)pubKeyData, NULL, &keyFormat, &keyType, 0, NULL, NULL, &cfImportedItems); NSArray *importedItems = (bridge NSArray*)cfImportedItems; if(!retval && importedItems && importedItems.count == 1) { SecKeyRef pubKeyAppleFormat = (bridge SecKeyRef)(importedItems[0]); CFErrorRef cfError = NULL; Boolean b = SecKeyIsAlgorithmSupported(pubKeyAppleFormat, kSecKeyOperationTypeDecrypt, kSecKeyAlgorithmRSAEncryptionPKCS1); NSLog(@"Algorithm supported: %d", b); CFDataRef cfDigestData = SecKeyCreateDecryptedData(pubKeyAppleFormat, kSecKeyAlgorithmRSAEncryptionPKCS1, (CFDataRef)signatureData, &cfError); if(!cfDigestData) { NSLog(@"SecKeyCreateDecryptedData error%@", (bridge NSError*)cfError); } else { NSLog(@"%@", (bridge NSData*)cfDigestData); } }
This gives me an error: SecKeyCreateDecryptedData errorError Domain=NSOSStatusErrorDomain Code=-50 "RSAdecrypt wrong input (err -27)" (paramErr: error in user parameter list) UserInfo={numberOfErrorsDeep=0, NSDescription=RSAdecrypt wrong input (err -27)}
Note that OpenSSL code above can decrypt this with RSA_PKCS1_PADDING argument.
If instead of kSecKeyAlgorithmRSAEncryptionPKCS1 I put kSecKeyAlgorithmRSAEncryptionRaw, I do get some bytes and no errors, however they are incorrect, as OpenSSL CLI uses PKCS1.
Is there a way to get a matching to OpenSSL signature verification via macOS APIs?
