Certificate file

GMSm2Bio is a tool class for processing SM2 key files. It supports reading and creating public and private keys in multiple formats such as PEM, DER, CER and PKCS#12, and supports password-protected certificate parsing.

Generate key pair files

The generated public and private key files are in the NSTemporaryDirectory() temporary folder path by default and will be automatically cleaned up.

GMSm2KeyFiles *pemKeyFiles = [GMSm2Bio generatePemKeyFiles];
NSString *pemPubKeyPath = pemKeyFiles.publicKeyPath; // sm2-pub.pem
NSString *pemPriKeyPath = pemKeyFiles.privateKeyPath; // sm2-pri.pem

GMSm2KeyFiles *derKeyFiles = [GMSm2Bio generateDerKeyFiles];
NSString *derPubKeyPath = derKeyFiles.publicKeyPath; // sm2-pub.der
NSString *derPriKeyPath = derKeyFiles.privateKeyPath; // sm2-pri.der

Read PEM/DER format

Note

• All returned public and private keys are HEX format strings
• Public keys start with 04 The private key starts with the identifier (uncompressed format), and the private key has no ciphertext format identifier
• The certificate password is an optional parameter. If there is no password protection, pass nil

// Read the PEM format public key
NSData *pubPemData = [NSData dataWithContentsOfFile:@"public.pem"];
NSString *publicKey = [GMSm2Bio readPublicKeyFromPemData:pemData password:nil];

// Read the PEM format private key with password
NSData *priPemData = [NSData dataWithContentsOfFile:@"private.pem"];
NSData *pwdData = [@"12345678" dataUsingEncoding:NSUTF8StringEncoding];
NSString *privateKey = [GMSm2Bio readPrivateKeyFromPemData:priPemData password:pwdData];

// Read DER format public and private keys
NSData *publicDerData = [NSData dataWithContentsOfFile:@"public.der"];
NSData *privateDerData = [NSData dataWithContentsOfFile:@"private.der"];
NSString *publicFromDer = [GMSm2Bio readPublicKeyFromDerData:publicDerData];
NSString *privateFromDer = [GMSm2Bio readPrivateKeyFromDerData:privateDerData];

Write PEM/DER format

GMSm2Key *keyPair = [GMSm2Utils generateKey];
NSString *pubKey = keyPair.publicKey; // Public key string starting with 04, HEX encoding format
NSString *priKey = keyPair.privateKey; // Private key string, HEX Encoding format

// File path to save public and private keys
NSString *tmpDir = NSTemporaryDirectory();
NSString *publicPemPath = [tmpDir stringByAppendingPathComponent:@"t-public.pem"];
NSString *publicDerPath = [tmpDir stringByAppendingPathComponent:@"t-public.der"];
NSString *privatePemPath = [tmpDir stringByAppendingPathComponent:@"t-private.pem"];
NSString *privateDerPath = [tmpDir stringByAppendingPathComponent:@"t-private.der"];

// Write public and private keys to PEM/DER files, return YES if writing is successful, otherwise return NO
BOOL success1 = [GMSm2Bio savePublicKey:pubKey toPemFileAtPath:publicPemPath];
BOOL success2 = [GMSm2Bio savePublicKey:pubKey toDerFileAtPath:publicDerPath];
BOOL success3 = [GMSm2Bio savePrivateKey:priKey toPemFileAtPath:privatePemPath];
BOOL success4 = [GMSm2Bio savePrivateKey:priKey toDerFileAtPath:privateDerPath];

Parse X.509 certificate

The readable certificate information includes (see GMSm2X509Info definition for details):

• Version number, serial number
• Public key and private key (HEX format)
• Validity period and expiration date
• Certificate fingerprint (SHA-1/SHA-256)
• Certificate subject information (country, organization, common name, etc.)
• Certificate issuer information

NSData *certData = [NSData dataWithContentsOfFile:@"certificate.cer"]; 
GMSm2X509Info *certInfo = [GMSm2Bio readX509InfoFromData:certData password:nil]; 
NSString *publicKey = certInfo.publicKey; 
NSString *commonName = certInfo.commonName;