Swift/URLSession returns 与 OpenSSL 不同的 public 密钥
Swift/URLSession returns a different public key than OpenSSL
我有这段代码（可以在操场上 运行）：
import UIKit
import CryptoKit
let url: URL = URL(string: "https://apple.com")!
final class SSLExtractor: NSObject, URLSessionDelegate {
private var session: URLSession!
init(url: URL) {
super.init()
let session = URLSession.init(configuration: .default, delegate: self, delegateQueue: nil)
session.dataTask(with: url).resume()
}
func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
guard challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust,
let serverTrust = challenge.protectionSpace.serverTrust,
let publicKey = SecTrustCopyKey(serverTrust),
let publicKeyData = SecKeyCopyExternalRepresentation(publicKey, nil)
else { return }
let publicKeyHash = SHA256.hash(data: publicKeyData as Data)
print("publicKey: \(publicKey)")
print("publicKey: \(publicKeyData)")
print("publicKey: \((publicKeyData as Data).base64EncodedString() )")
print(publicKeyHash)
}
}
let extractor = SSLExtractor(url: url)
据推测最后打印应该给我服务器的 public 密钥：
SHA256 digest: b0faa00170de7c1ac7994644efadb59f149656546394bd22c95527e78f1984b6
但是，当我使用 OpenSSL 时：
$ openssl s_client -connect apple.com:443 | openssl x509 -pubkey -noout | openssl rsa -pubin -outform der| openssl dgst -sha256
我得到了一个不同的哈希值：
1786e93d8e16512ea34ea1475e39597e77d7e39239ba1a97dcd71f97e64d6619
如何获得正确的哈希值？
编辑：也尝试过
let certificate = SecTrustGetCertificateAtIndex(serverTrust, 0),
let certifKey = SecCertificateCopyKey(certificate),
let certifPubKey = SecKeyCopyPublicKey(certifKey),
let certifPubKeyData = SecKeyCopyExternalRepresentation(certifPubKey, nil)
但我得到了相同的结果
只是一个答案，但评论太多了。您发现 'external' public 由 Swift 提供（并散列）的密钥是 OpenSSL 使用的密钥的后缀。
正如我所引用的，OpenSSL 使用由 X.509/PKIX=RFC5280 section 4 which is a DER-encoded ASN.1 SEQUENCE containing an AlgorithmIdentifier and a BIT STRING cotaining embedded algorithm-specific data. RFC 7468 section 13 (which partly officializes OpenSSL, although it doesn't say so) confirms this is the content of a 'standard' public key representation, and RFC 3279 section 2.3.1 defines that for RSA (which the Apple cert's key is) the content of the BIT STRING part is the ASN.1 structure RSAPublicKey which actually was defined (though 3279 doesn't say so for the key, while it does for the signature in 2.2.1) in PKCS1 currently RFC8017 section A.1.1 定义的 'SPKI' (SubjectPublicKeyInfo) 结构（但与早期版本没有变化）。
由于 DER 编码的工作方式，BIT STRING 的内容——在本例中为 ASN.1 结构 RSAPublicKey——恰好是整个 SPKI 编码的后缀。
如果我们查看并解析 SPKI OpenSSL 从证书中获取（x509 -pubkey）
$ openssl rsa -pubin -in applespki -outform der |od -Ax -tx1
writing RSA key
000000 30 82 01 22 30 0d 06 09 2a 86 48 86 f7 0d 01 01
000010 01 05 00 03 82 01 0f 00 30 82 01 0a 02 82 01 01
000020 00 e0 e5 ca aa 34 ea 32 d1 f5 e3 56 e5 05 e8 07
000030 c3 d3 3b 86 93 60 94 37 20 9f 8d d0 17 8f ba da
000040 16 f1 b2 6a bc 41 7a 6f dc 22 87 4b 05 e8 57 48
000050 56 3c da a2 02 e5 57 73 94 95 18 dd 7c c9 b0 68
000060 fe 17 2c 8b 6f fa 42 a9 b1 a8 77 88 22 d4 41 08
000070 08 d9 80 59 92 bc e9 3a 0a 17 e0 2b 13 fe bf ec
000080 69 7d 61 15 14 21 71 73 a0 70 fd 6d a0 0f 46 13
000090 60 8d c1 bd 8c 66 60 04 05 e0 44 f0 a1 53 b7 00
0000a0 7f a3 f3 55 da d2 6c c6 dd 7f 83 79 1f 6e cb 1d
0000b0 78 3e d9 9f fa 58 34 38 41 c5 70 c1 c7 dd ea b0
0000c0 81 c0 d4 a3 18 a4 da 02 15 b8 cb 48 10 fa 42 86
0000d0 75 1c 55 51 6b 48 6e 37 43 98 09 af 4f 52 c0 c8
0000e0 75 40 a5 e7 65 ba 62 2a be 6c 2a 6d 72 5b 82 21
0000f0 d1 75 97 ea 7e 21 a1 04 f4 76 7c 85 db 50 c7 9f
000100 b5 d8 f7 80 15 ba a5 83 9e 2c da f0 73 c6 14 9a
000110 fd 35 07 41 4b 53 21 8d 0d 01 f1 05 b3 04 05 83
000120 cb 02 03 01 00 01
000126
$ openssl asn1parse -i -dump -in applespki1
0:d=0 hl=4 l= 290 cons: SEQUENCE
4:d=1 hl=2 l= 13 cons: SEQUENCE
6:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
17:d=2 hl=2 l= 0 prim: NULL
19:d=1 hl=4 l= 271 prim: BIT STRING
0000 - 00 30 82 01 0a 02 82 01-01 00 e0 e5 ca aa 34 ea .0............4.
0010 - 32 d1 f5 e3 56 e5 05 e8-07 c3 d3 3b 86 93 60 94 2...V......;..`.
0020 - 37 20 9f 8d d0 17 8f ba-da 16 f1 b2 6a bc 41 7a 7 ..........j.Az
0030 - 6f dc 22 87 4b 05 e8 57-48 56 3c da a2 02 e5 57 o.".K..WHV<....W
0040 - 73 94 95 18 dd 7c c9 b0-68 fe 17 2c 8b 6f fa 42 s....|..h..,.o.B
0050 - a9 b1 a8 77 88 22 d4 41-08 08 d9 80 59 92 bc e9 ...w.".A....Y...
0060 - 3a 0a 17 e0 2b 13 fe bf-ec 69 7d 61 15 14 21 71 :...+....i}a..!q
0070 - 73 a0 70 fd 6d a0 0f 46-13 60 8d c1 bd 8c 66 60 s.p.m..F.`....f`
0080 - 04 05 e0 44 f0 a1 53 b7-00 7f a3 f3 55 da d2 6c ...D..S.....U..l
0090 - c6 dd 7f 83 79 1f 6e cb-1d 78 3e d9 9f fa 58 34 ....y.n..x>...X4
00a0 - 38 41 c5 70 c1 c7 dd ea-b0 81 c0 d4 a3 18 a4 da 8A.p............
00b0 - 02 15 b8 cb 48 10 fa 42-86 75 1c 55 51 6b 48 6e ....H..B.u.UQkHn
00c0 - 37 43 98 09 af 4f 52 c0-c8 75 40 a5 e7 65 ba 62 7C...OR..u@..e.b
00d0 - 2a be 6c 2a 6d 72 5b 82-21 d1 75 97 ea 7e 21 a1 *.l*mr[.!.u..~!.
00e0 - 04 f4 76 7c 85 db 50 c7-9f b5 d8 f7 80 15 ba a5 ..v|..P.........
00f0 - 83 9e 2c da f0 73 c6 14-9a fd 35 07 41 4b 53 21 ..,..s....5.AKS!
0100 - 8d 0d 01 f1 05 b3 04 05-83 cb 02 03 01 00 01 ...............
我们可以看到BIT STRING的内容，由于DER对BIT STRING的工作方式，跳过了第一个字节00，因此从偏移量24=0x18开始一直持续到最后，本身就是一个DER编码RSAPublicKey（30 82 01 0a 是序列，02 82 01 01 ... 是整数（有符号）模数，02 03 01 00 01 是整数（有符号）public 指数）。 OpenSSL 1.0.0 up（现在无处不在，虽然我记得它不是）可以提取它，并获得你期望的哈希值：
$ openssl rsa -pubin -in applespki -RSAPublicKey_out -outform der |od -Ax -tx1
writing RSA key
000000 30 82 01 0a 02 82 01 01 00 e0 e5 ca aa 34 ea 32
000010 d1 f5 e3 56 e5 05 e8 07 c3 d3 3b 86 93 60 94 37
000020 20 9f 8d d0 17 8f ba da 16 f1 b2 6a bc 41 7a 6f
000030 dc 22 87 4b 05 e8 57 48 56 3c da a2 02 e5 57 73
000040 94 95 18 dd 7c c9 b0 68 fe 17 2c 8b 6f fa 42 a9
000050 b1 a8 77 88 22 d4 41 08 08 d9 80 59 92 bc e9 3a
000060 0a 17 e0 2b 13 fe bf ec 69 7d 61 15 14 21 71 73
000070 a0 70 fd 6d a0 0f 46 13 60 8d c1 bd 8c 66 60 04
000080 05 e0 44 f0 a1 53 b7 00 7f a3 f3 55 da d2 6c c6
000090 dd 7f 83 79 1f 6e cb 1d 78 3e d9 9f fa 58 34 38
0000a0 41 c5 70 c1 c7 dd ea b0 81 c0 d4 a3 18 a4 da 02
0000b0 15 b8 cb 48 10 fa 42 86 75 1c 55 51 6b 48 6e 37
0000c0 43 98 09 af 4f 52 c0 c8 75 40 a5 e7 65 ba 62 2a
0000d0 be 6c 2a 6d 72 5b 82 21 d1 75 97 ea 7e 21 a1 04
0000e0 f4 76 7c 85 db 50 c7 9f b5 d8 f7 80 15 ba a5 83
0000f0 9e 2c da f0 73 c6 14 9a fd 35 07 41 4b 53 21 8d
000100 0d 01 f1 05 b3 04 05 83 cb 02 03 01 00 01
00010e
$ openssl rsa -pubin -in applespki -RSAPublicKey_out -outform der |openssl sha256
writing RSA key
(stdin)= b0faa00170de7c1ac7994644efadb59f149656546394bd22c95527e78f1984b6
这仅适用于 RSA。看看您的 Swift 代码如何处理经过认证的 non-RSA 密钥可能会很有趣，尽管目前很难在 public 网络上找到它们；我目前知道的唯一稳定的是 'badssl' 像 https://ecc256.badssl.com .
我有这段代码（可以在操场上 运行）：
import UIKit
import CryptoKit
let url: URL = URL(string: "https://apple.com")!
final class SSLExtractor: NSObject, URLSessionDelegate {
private var session: URLSession!
init(url: URL) {
super.init()
let session = URLSession.init(configuration: .default, delegate: self, delegateQueue: nil)
session.dataTask(with: url).resume()
}
func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
guard challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust,
let serverTrust = challenge.protectionSpace.serverTrust,
let publicKey = SecTrustCopyKey(serverTrust),
let publicKeyData = SecKeyCopyExternalRepresentation(publicKey, nil)
else { return }
let publicKeyHash = SHA256.hash(data: publicKeyData as Data)
print("publicKey: \(publicKey)")
print("publicKey: \(publicKeyData)")
print("publicKey: \((publicKeyData as Data).base64EncodedString() )")
print(publicKeyHash)
}
}
let extractor = SSLExtractor(url: url)
据推测最后打印应该给我服务器的 public 密钥：
SHA256 digest: b0faa00170de7c1ac7994644efadb59f149656546394bd22c95527e78f1984b6
但是，当我使用 OpenSSL 时：
$ openssl s_client -connect apple.com:443 | openssl x509 -pubkey -noout | openssl rsa -pubin -outform der| openssl dgst -sha256
我得到了一个不同的哈希值：
1786e93d8e16512ea34ea1475e39597e77d7e39239ba1a97dcd71f97e64d6619
如何获得正确的哈希值？
编辑：也尝试过
let certificate = SecTrustGetCertificateAtIndex(serverTrust, 0),
let certifKey = SecCertificateCopyKey(certificate),
let certifPubKey = SecKeyCopyPublicKey(certifKey),
let certifPubKeyData = SecKeyCopyExternalRepresentation(certifPubKey, nil)
但我得到了相同的结果
只是一个答案，但评论太多了。您发现 'external' public 由 Swift 提供（并散列）的密钥是 OpenSSL 使用的密钥的后缀。
正如我所引用的，OpenSSL 使用由 X.509/PKIX=RFC5280 section 4 which is a DER-encoded ASN.1 SEQUENCE containing an AlgorithmIdentifier and a BIT STRING cotaining embedded algorithm-specific data. RFC 7468 section 13 (which partly officializes OpenSSL, although it doesn't say so) confirms this is the content of a 'standard' public key representation, and RFC 3279 section 2.3.1 defines that for RSA (which the Apple cert's key is) the content of the BIT STRING part is the ASN.1 structure RSAPublicKey which actually was defined (though 3279 doesn't say so for the key, while it does for the signature in 2.2.1) in PKCS1 currently RFC8017 section A.1.1 定义的 'SPKI' (SubjectPublicKeyInfo) 结构（但与早期版本没有变化）。
由于 DER 编码的工作方式，BIT STRING 的内容——在本例中为 ASN.1 结构 RSAPublicKey——恰好是整个 SPKI 编码的后缀。
如果我们查看并解析 SPKI OpenSSL 从证书中获取（x509 -pubkey）
$ openssl rsa -pubin -in applespki -outform der |od -Ax -tx1
writing RSA key
000000 30 82 01 22 30 0d 06 09 2a 86 48 86 f7 0d 01 01
000010 01 05 00 03 82 01 0f 00 30 82 01 0a 02 82 01 01
000020 00 e0 e5 ca aa 34 ea 32 d1 f5 e3 56 e5 05 e8 07
000030 c3 d3 3b 86 93 60 94 37 20 9f 8d d0 17 8f ba da
000040 16 f1 b2 6a bc 41 7a 6f dc 22 87 4b 05 e8 57 48
000050 56 3c da a2 02 e5 57 73 94 95 18 dd 7c c9 b0 68
000060 fe 17 2c 8b 6f fa 42 a9 b1 a8 77 88 22 d4 41 08
000070 08 d9 80 59 92 bc e9 3a 0a 17 e0 2b 13 fe bf ec
000080 69 7d 61 15 14 21 71 73 a0 70 fd 6d a0 0f 46 13
000090 60 8d c1 bd 8c 66 60 04 05 e0 44 f0 a1 53 b7 00
0000a0 7f a3 f3 55 da d2 6c c6 dd 7f 83 79 1f 6e cb 1d
0000b0 78 3e d9 9f fa 58 34 38 41 c5 70 c1 c7 dd ea b0
0000c0 81 c0 d4 a3 18 a4 da 02 15 b8 cb 48 10 fa 42 86
0000d0 75 1c 55 51 6b 48 6e 37 43 98 09 af 4f 52 c0 c8
0000e0 75 40 a5 e7 65 ba 62 2a be 6c 2a 6d 72 5b 82 21
0000f0 d1 75 97 ea 7e 21 a1 04 f4 76 7c 85 db 50 c7 9f
000100 b5 d8 f7 80 15 ba a5 83 9e 2c da f0 73 c6 14 9a
000110 fd 35 07 41 4b 53 21 8d 0d 01 f1 05 b3 04 05 83
000120 cb 02 03 01 00 01
000126
$ openssl asn1parse -i -dump -in applespki1
0:d=0 hl=4 l= 290 cons: SEQUENCE
4:d=1 hl=2 l= 13 cons: SEQUENCE
6:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
17:d=2 hl=2 l= 0 prim: NULL
19:d=1 hl=4 l= 271 prim: BIT STRING
0000 - 00 30 82 01 0a 02 82 01-01 00 e0 e5 ca aa 34 ea .0............4.
0010 - 32 d1 f5 e3 56 e5 05 e8-07 c3 d3 3b 86 93 60 94 2...V......;..`.
0020 - 37 20 9f 8d d0 17 8f ba-da 16 f1 b2 6a bc 41 7a 7 ..........j.Az
0030 - 6f dc 22 87 4b 05 e8 57-48 56 3c da a2 02 e5 57 o.".K..WHV<....W
0040 - 73 94 95 18 dd 7c c9 b0-68 fe 17 2c 8b 6f fa 42 s....|..h..,.o.B
0050 - a9 b1 a8 77 88 22 d4 41-08 08 d9 80 59 92 bc e9 ...w.".A....Y...
0060 - 3a 0a 17 e0 2b 13 fe bf-ec 69 7d 61 15 14 21 71 :...+....i}a..!q
0070 - 73 a0 70 fd 6d a0 0f 46-13 60 8d c1 bd 8c 66 60 s.p.m..F.`....f`
0080 - 04 05 e0 44 f0 a1 53 b7-00 7f a3 f3 55 da d2 6c ...D..S.....U..l
0090 - c6 dd 7f 83 79 1f 6e cb-1d 78 3e d9 9f fa 58 34 ....y.n..x>...X4
00a0 - 38 41 c5 70 c1 c7 dd ea-b0 81 c0 d4 a3 18 a4 da 8A.p............
00b0 - 02 15 b8 cb 48 10 fa 42-86 75 1c 55 51 6b 48 6e ....H..B.u.UQkHn
00c0 - 37 43 98 09 af 4f 52 c0-c8 75 40 a5 e7 65 ba 62 7C...OR..u@..e.b
00d0 - 2a be 6c 2a 6d 72 5b 82-21 d1 75 97 ea 7e 21 a1 *.l*mr[.!.u..~!.
00e0 - 04 f4 76 7c 85 db 50 c7-9f b5 d8 f7 80 15 ba a5 ..v|..P.........
00f0 - 83 9e 2c da f0 73 c6 14-9a fd 35 07 41 4b 53 21 ..,..s....5.AKS!
0100 - 8d 0d 01 f1 05 b3 04 05-83 cb 02 03 01 00 01 ...............
我们可以看到BIT STRING的内容，由于DER对BIT STRING的工作方式，跳过了第一个字节00，因此从偏移量24=0x18开始一直持续到最后，本身就是一个DER编码RSAPublicKey（30 82 01 0a 是序列，02 82 01 01 ... 是整数（有符号）模数，02 03 01 00 01 是整数（有符号）public 指数）。 OpenSSL 1.0.0 up（现在无处不在，虽然我记得它不是）可以提取它，并获得你期望的哈希值：
$ openssl rsa -pubin -in applespki -RSAPublicKey_out -outform der |od -Ax -tx1
writing RSA key
000000 30 82 01 0a 02 82 01 01 00 e0 e5 ca aa 34 ea 32
000010 d1 f5 e3 56 e5 05 e8 07 c3 d3 3b 86 93 60 94 37
000020 20 9f 8d d0 17 8f ba da 16 f1 b2 6a bc 41 7a 6f
000030 dc 22 87 4b 05 e8 57 48 56 3c da a2 02 e5 57 73
000040 94 95 18 dd 7c c9 b0 68 fe 17 2c 8b 6f fa 42 a9
000050 b1 a8 77 88 22 d4 41 08 08 d9 80 59 92 bc e9 3a
000060 0a 17 e0 2b 13 fe bf ec 69 7d 61 15 14 21 71 73
000070 a0 70 fd 6d a0 0f 46 13 60 8d c1 bd 8c 66 60 04
000080 05 e0 44 f0 a1 53 b7 00 7f a3 f3 55 da d2 6c c6
000090 dd 7f 83 79 1f 6e cb 1d 78 3e d9 9f fa 58 34 38
0000a0 41 c5 70 c1 c7 dd ea b0 81 c0 d4 a3 18 a4 da 02
0000b0 15 b8 cb 48 10 fa 42 86 75 1c 55 51 6b 48 6e 37
0000c0 43 98 09 af 4f 52 c0 c8 75 40 a5 e7 65 ba 62 2a
0000d0 be 6c 2a 6d 72 5b 82 21 d1 75 97 ea 7e 21 a1 04
0000e0 f4 76 7c 85 db 50 c7 9f b5 d8 f7 80 15 ba a5 83
0000f0 9e 2c da f0 73 c6 14 9a fd 35 07 41 4b 53 21 8d
000100 0d 01 f1 05 b3 04 05 83 cb 02 03 01 00 01
00010e
$ openssl rsa -pubin -in applespki -RSAPublicKey_out -outform der |openssl sha256
writing RSA key
(stdin)= b0faa00170de7c1ac7994644efadb59f149656546394bd22c95527e78f1984b6
这仅适用于 RSA。看看您的 Swift 代码如何处理经过认证的 non-RSA 密钥可能会很有趣，尽管目前很难在 public 网络上找到它们；我目前知道的唯一稳定的是 'badssl' 像 https://ecc256.badssl.com .