The key, message, and signature come from Example 1 of: ftp://ftp.rsa.com/pub/rsalabs/tmp/pkcs1v15sign-vectors.txt (The algorithm DER was synthesized to match, and the signature enclosed in a BIT STRING). It uses an RSA key with modulus length of 1024 bits, PKCS#1 v1.5 padding, and SHA-1 as the digest. -----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQClbkoOcBAXWJpRh9x+qEHRVvLsDjatUqRN/rH mH3rZkdjFEFb/7bFitMDyg6EqiKOU3/Umq3KRy7MHzqv84LHf1c2VCAltWyuLbfXWce9jd8CSHL I8Jwpw4lmOb/idGfEFrMLT8Ms18pKA4Thrb2TE7yLh4fINDOjP+yJJvZohNwIDAQAB -----END PUBLIC KEY----- $ openssl asn1parse -i < [PUBLIC KEY] 0:d=0 hl=3 l= 159 cons: SEQUENCE 3:d=1 hl=2 l= 13 cons: SEQUENCE 5:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption 16:d=2 hl=2 l= 0 prim: NULL 18:d=1 hl=3 l= 141 prim: BIT STRING -----BEGIN ALGORITHM----- MA0GCSqGSIb3DQEBBQUA -----END ALGORITHM----- $ openssl asn1parse -i < [ALGORITHM] 0:d=0 hl=2 l= 13 cons: SEQUENCE 2:d=1 hl=2 l= 9 prim: OBJECT :sha1WithRSAEncryption 13:d=1 hl=2 l= 0 prim: NULL -----BEGIN DATA----- zch9oiPXht87ReC7vHITJtHuKvgGzDFUdcxvDZxm4bYjcdRc4jkuGskoRMMQEC8Vag2NUsH0xAu jqmUJV4bLdpdXplY7qVj+0LzJhOi1F6PV9RWyO4pB50qoZ2k/kN+wYabobfqu5kRywA5fIJRXKc vr538Gznjgj0CY+6QfnWGTwDF+i2DUtghKy0LSnjgIo7w3LYXjMRcPy/fMctC3HClmSLOk0Q9BY pXQgHqmJcqydE/Z6o/SI8QlNwKYKL0WvgJUbxMP0uM7k20mduCK7RtzMYt1CgFn0A== -----END DATA----- -----BEGIN SIGNATURE----- A4GBAGvDoGZWhCkwokfjDVhktNgZI2unxollhirX28TiSvKOhrtTHwM1i+X7dHd8YIb4UMrviT8 Nb8wtDJHsATaTtOoAuAzUmqxOy1+JEa/lOa2kqPOCPR0T5HLRSQVHxlnHYX89JAh9228rcglhZ/ wJfKsY6aRY/LY0zc6O41iUxITX -----END SIGNATURE----- $ openssl asn1parse -i < [SIGNATURE] 0:d=0 hl=3 l= 129 prim: BIT STRING