1This test data was produced by creating a self-signed RSA cert using OpenSSL, 2and then extracting the relevant fields. 3 4It uses RSA PKCS#1 v1.5 with SHA-512 and a 2048-bit key. 5 6(1) Generate self-signed certificate 7 8 openssl genrsa -out rsa_key.pem 2048 9 openssl req -new -key rsa_key.pem -x509 -nodes -days 365 -sha512 -out cert.pem 10 11(2) Extract public key 12 13 openssl x509 -in cert.pem -pubkey -noout > pubkey.pem 14 cat pubkey.pem 15 16(3) Extract signed data (tbsCertificate) 17 18 openssl asn1parse -in cert.pem -out tbs -noout -strparse 4 19 base64 tbs 20 21(4) Extract signature algorithm 22 23 # Find the offset of the signature algorithm near the end (589 in this case) 24 openssl asn1parse -in cert.pem 25 26 openssl asn1parse -in cert.pem -out alg -noout -strparse 589 27 base64 alg 28 29(5) Extract the signature 30 31 # Find the final offset of BIT STRING (506 in this case) 32 openssl asn1parse -in cert.pem 33 34 openssl asn1parse -in cert.pem -out sig -noout -strparse 506 35 base64 sig 36 37 38$ openssl asn1parse -i < [PUBLIC KEY] 39 0:d=0 hl=4 l= 290 cons: SEQUENCE 40 4:d=1 hl=2 l= 13 cons: SEQUENCE 41 6:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption 42 17:d=2 hl=2 l= 0 prim: NULL 43 19:d=1 hl=4 l= 271 prim: BIT STRING 44-----BEGIN PUBLIC KEY----- 45MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAzcu2shJRrXFAwMkf30y2AY1zIg9VF/h 46egYcejzdR2AzUb8vU2TXld2i8pp44l+DrvtqmzS7G+yxx3uOx+zsoqBaUT0c9HfkbE+IRmcLkQF 47vYpSpm6Eu8OS14CSmEtiR91Et8LR0+bd0Gn3pgmb+epFJBaBPeDSiI/smqKCs7yP04+tS4Q4r47 48G04LhSp4/hmqH32b4Gcm9nsihHV9FfPfVdxDQUEJp3AgyBPwhPZEAyhoQS73TjjxXHqJRSz37Sl 49ueMVPuNncqbT4nAMKz25J1CtRlQh21uZzfY2QRP3m6rAZquQUos1febC6A7qmhQljWKKmXtfVY+ 50fAamstdHrWwIDAQAB 51-----END PUBLIC KEY----- 52 53$ openssl asn1parse -i < [ALGORITHM] 54 0:d=0 hl=2 l= 13 cons: SEQUENCE 55 2:d=1 hl=2 l= 9 prim: OBJECT :sha512WithRSAEncryption 56 13:d=1 hl=2 l= 0 prim: NULL 57-----BEGIN ALGORITHM----- 58MA0GCSqGSIb3DQEBDQUA 59-----END ALGORITHM----- 60 61-----BEGIN DATA----- 62MIICRaADAgECAgkA7jWRLkwHvHswDQYJKoZIhvcNAQENBQAwRTELMAkGA1UEBhMCQVUxEzARBgN 63VBAgMClNvbWUtU3RhdGUxITAfBgNVBAoMGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDAeFw0xNT 64A3MjgwMjIyMzFaFw0xNjA3MjcwMjIyMzFaMEUxCzAJBgNVBAYTAkFVMRMwEQYDVQQIDApTb21lL 65VN0YXRlMSEwHwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwggEiMA0GCSqGSIb3DQEB 66AQUAA4IBDwAwggEKAoIBAQDNy7ayElGtcUDAyR/fTLYBjXMiD1UX+F6Bhx6PN1HYDNRvy9TZNeV 673aLymnjiX4Ou+2qbNLsb7LHHe47H7OyioFpRPRz0d+RsT4hGZwuRAW9ilKmboS7w5LXgJKYS2JH 683US3wtHT5t3QafemCZv56kUkFoE94NKIj+yaooKzvI/Tj61LhDivjsbTguFKnj+GaoffZvgZyb2 69eyKEdX0V899V3ENBQQmncCDIE/CE9kQDKGhBLvdOOPFceolFLPftKW54xU+42dyptPicAwrPbkn 70UK1GVCHbW5nN9jZBE/ebqsBmq5BSizV95sLoDuqaFCWNYoqZe19Vj58Bqay10etbAgMBAAGjUDB 71OMB0GA1UdDgQWBBRsCPajkEscZM6SpLbNTa/7dY5azzAfBgNVHSMEGDAWgBRsCPajkEscZM6SpL 72bNTa/7dY5azzAMBgNVHRMEBTADAQH/ 73-----END DATA----- 74 75$ openssl asn1parse -i < [SIGNATURE] 76 0:d=0 hl=4 l= 257 prim: BIT STRING 77-----BEGIN SIGNATURE----- 78A4IBAQAhKSNq+X/CfzhtNsMo6MJpTBjJBV5fhHerIZr6e3ozCTBCR29vYsVnJ4/6i5lL1pNeOhM 79ldthnuSlMzTS1Zme1OqRWB3U8QmwCFwhDxW/i4fdT8kxDAmELNp4z0GcXbe27V895PE0R/m8P47 80B6xbra+SQlEMW12K1EndUqrO6vgLbobV14mveWdgc0KIOnDKgsTHV8NTV1w3qtp1ujfvizYfBZu 81yyMOA1yZPDpREZtClro7lufwDQ7+LgSdtNLMDAMzapfIjAEPVNVLmJzMgzaHqMsZM8gP8vWAdfc 82R4mCmWXVotrM6d1rjJGdRADAONYCC4/+d1IMkVGoVfpaej6I 83-----END SIGNATURE----- 84